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2 3 This reference book was created using the Ohio Department of Education Mathematics Standards for 7th grade and the Lebanon City Schools 7th Grade Pre-Algebra Pacing Guide. I have done extensive studying and researched many articles to provide the most accurate information. I have looked at techniques that will enable students to obtain the greatest benefit in Mathematics Education. This reference book is meant to be a guide and tool for students and parents to use when they need extra information and resources on topics that are being studied in class. Review Topics Decimal Place Value…………………………………………… Adding and Subtracting Decimals…………………………... Multiplying and Dividing Decimals…………………………… Repeating/Terminating Decimals……………………………. Rounding…………………………………………………………. Equivalent Fractions……………………………………………. . Adding and Subtracting Fractions…………………………… Multiplying and Dividing Fractions…………………………… Long Division……………………………………………………… 6 7 7 8 9 9 10 11 12 Number Sense Absolute Value………………………………………………….. Exponents………………………………………………………... Scientific Notation……………………………………………… Adding and Subtracting Integers…………………………… Multiplying and Dividing Integers……………………………. Order of Operations……………………………………………. One and Two Step Equations………………………………… Percent and Percent Proportions……………………………. Percent of Increase/Decrease……………………………….. Sales Tax and Discounts……………………………………….. 15 15 16 18 19 20 21 23 26 Patterns, Functions and Algebra Sequences………………………………………………………. Finding Patterns………………………………………………… Input/Output Tables……………………………………………. Coordinate Plane………………………………………………. Slope and y-intercept……………………………………….... Graphing Equations……………………………………………. Solve Inequalities……………………………………………….. Simplifying Expressions (combine like terms)………………. 29 30 31 33 35 37 40 42 5 Measurement and Geometry Customary Unit Conversion………………………………….. Metric Unit Conversion………………………………………… Geometric Shapes…………………………………………….. Perimeter………………………………………………………… Area………………………………………………………………. Surface Area……………………………………………………. Volume…………………………………………………………… Scale Factor/Proportions……………………………………… Types of Triangles……………………………………………….. Pythagoreans Theorem……………………………………….. Translation, Rotation, Reflection, Dilation………………….. 44 45 47 47 48 50 53 55 56 57 59 Data Analysis and Probability Measures of Central Tendency……………………………… Scatter plot……………………………………………………….. Histogram………………………………………………………… Box and Whiskers……………………………………………….. Stem and Leaf Plot…………………………………………….. Bar Graph………………………………………………………… Circle Graph……………………………………………………… Probability………………………………………………………... Theoretical Probability…………………………………………. Experimental Probability……………………………………… Tree Diagram……………………………………………………. Simple Probability………………………………………………. Compound Probability………………………………………… 62 63 64 65 67 69 70 71 72 72 74 75 76 Glossary of Terms………………………………………………………. 78 Technology Links………………………………………………………. 87 Homework Help……………………………………………………….. 96 Ohio State Standards………………………………………………… 99 Real Number Properties Review……………………………………. 101 Multiplication Chart……………………………………………………. 102 6 7 Decimal Place Value . Tenths Hundredths Thousandths Ten thousandths Do you notice that the decimal point separates whole numbers from decimals? Decimals are parts of a whole number and are another way of expressing a fraction. In other words, 0.7 can also be expressed as . When reading a decimal aloud, you would say: 1. The whole number 2. (And ) for the decimal point 3. The whole number of the decimal with the place value of the last digit. Example: 21,300.25 Twenty-one thousand three hundred AND twenty-five hundredths 8 Adding and Subtracting Decimals When adding and subtracting decimals you MUST line up the decimal points in the problem. Use place holding zeros when necessary. For example: 12 – 4.08 = AND 4.26 + 13.77= 12.00 - 4.08 7.92 13.77 + 4.26 18.03 Be sure to line up the decimals! Multiplying and Dividing Decimals When multiplying decimals, don’t consider the decimals until after you have multiplied. Then, count the number of digits BEHIND the decimal(s) in the problem. This is how many space you will move the decimal to the LEFT in your answer. For example: .004 x .02= .004 x.02 .00008 4x2=8 There are 5 digits behind the decimals in the problem 8.0 → move decimal 5 places left → .00008 If the number in a division box has a decimal, but the number outside of the division box does not have a decimal, place the decimal point in the quotient (the answer) directly above the decimal point in the division box. Divide normally. .002 5 0.010 9 If the number outside of the division box has a decimal, but the number inside of the division box does not, move the decimal on the outside number however many places needed to make it a whole number. Then to the right of the number in the division box (a whole number with an "understood decimal" at the end) add as many zeros to match the number of places the decimal was moved on the outside number. Place the decimal point in the quotient directly above the new decimal place in the division box. 20 0.05 1 0.05 1.00 5 100 If both the numbers inside and outside of the division box have decimals, count how many places are needed to move the decimal point outside of the division box (the divisor) to make it a whole number. Move the decimal point in the number inside of the division box (the dividend) the same number of places. Place the decimal point in the quotient (the answer) directly above the new decimal point. .2 .05 .01 5 1 5 1.0 Repeating Decimal A decimal that repeats in a specific pattern over and over. It never terminates or stops. Example: 1 = .3333 3 The line over the decimal indicates it is repeating. Terminating Decimal A decimal that terminates, means it stops at a certain point. Example: ¾ = .75 10 Rounding When rounding, determine which place value you need to round to. Underline that digit. Look to the right. This digit will determine if your underlined digit stays the same or goes up one digit. Make the changes (if necessary) to the digit then fill in the rest of the places with zeros. 4 and below= stay the same 5 and above= move up one digit Example: Round to the nearest hundreds place. 2,542 → 2,500 The number to the right of the hundreds digit is a 4. You would keep the hundreds digit the same. Then the 4 and 2 need to be replaced with zeros. Round to the nearest thousands place. 67,902 → 68,000 Equivalent Fractions Equivalent fractions are fractions that have the same value. 1 2 2 4 We often use equivalent fractions when reducing fractions to their lowest terms. We do this by finding the greatest common factor of the numerator and denominator. We then divide the numerator and denominator by the GCF to get the equivalent fraction. 27 27 9 3 GCF 9 36 36 9 4 GCF = Greatest Common Factor 11 Adding and Subtracting Fractions When the denominators are the same, you may add and subtract across the numerator with out making any changes. The denominator always stays the same. 1 2 3 5 5 5 Example: or 7 3 4 8 8 8 When the denominators are different, you must find a common denominator. This is done by finding the least common multiple (LCM) of the numerator and denominator. Then you must use the LCM as the denominator for both fractions. Make equivalent fractions for each fraction in the problem. 5= 5, 10, 15, 20 3 1 Example: Multiplies of 3= 3,6, 9, 12, 15, 18 5 3 LCM = 15 Find equivalent fractions, 3 3 3 9 1 1 5 5 and 5 5 3 15 3 3 5 15 So… 9 5 14 15 15 15 The same rules apply for subtracting fractions 5 1 6 2 Example : Multiples of 2= 2, 4, 6 6= 6,12,18 5 stays 6 LCM = 6 and 1 1 3 3 2 23 6 5 3 2 22 1 reduces 6 6 6 62 3 12 Multiplying and Dividing Fractions When multiplying fractions, multiply across the numerators and denominators. Put your answer in lowest terms (simplest form/reduce) when necessary. 3 4 12 7 5 35 3 2 6 66 1 9 3 18 18 6 3 or When dividing fractions, follow the K= Keep C=Change rule. F=Flip In a division problem keep the first fraction the same, change the division sign to a multiplication sign, flip or find the reciprocal of the second fraction. 3 4 4 5 becomes 3 5 4 4 Multiply across 3 5 15 4 4 16 ALWAYS REDUCE TO LOWEST TERMS! 13 Long Division 1. Write the dividend and divisor in this form: The procedure involves dividing the divisor (4) into a number for each digit of the dividend (950). 2.The first number to be divided by the divisor (4) is the leftmost digit (9) of the dividend. Ignoring any remainder, write the result (2), above the line over the leftmost digit of the dividend. Multiply the divisor by that number (4 times 2) and write the result (8) under the leftmost digit of the dividend. 3. Subtract the bottom number (8) from the number immediately above it (9). Write the result (1), under the bottom number (8), then copy the next digit of the dividend (5) to the right of the result of the subtraction. 4. Repeat steps 2 and 3, using the newly created bottom number (15) as the number to be divided by the divisor (4), and write the results above and under the next digit of the dividend. 14 5. Repeat step 4 until there are no digits remaining in the dividend. The number written above the bar (237) is the quotient, and the result of the last subtraction is the remainder for the entire problem (2). The answer to the above example is expressed as 237 with remainder 2. Alternatively, one can continue the above procedure to produce a decimal answer. We continue the process by adding a decimal and zeroes as necessary to the right of the dividend, treating each zero as another digit of the dividend. Thus the next step in such a calculation would give the following: Be patient Follow the rules! 15 16 Absolute Value Absolute value is the absolutely positive value of any number. It is represented when a positive or negative integer has a bar on each side of the digit. 6 or 8 To find the absolute value of a number, you just take the positive value of the given number. 10 10 and 16 16 Exponents An exponent is made up of an exponent and a base. A base, tells you the number you will be multiplying. A exponent, tells you how many times to multiply the base by itself. 64 6 (the base) will be multiplied by itself 4 (the exponent) times. 6 x 6 x 6 x 6 = 1296 17 Scientific Notation Numbers expressed in scientific notation are written as the product (multiplication) of a factor and a power of 10 The first factor is always > than or = to 1 AND < 10 The second factor is always the number 10 with an exponent For example: 2 x 10³ → Correct To take a number from standard form to scientific notation, put a decimal after the first digit. Count the number of digits (including zeros) to the RIGHT of the decimal. The number of digits will be your exponent for the second factor. The speed of light is 670,000,000 miles per hour. This in scientific notation would look like this: 6.7 x 108 1. Place the decimal point after the first digit (which makes the factor greater than 1 but less than 10) 6.70,000,000 2. Count the number of digits to the RIGHT of the decimal point. 8 3. So… since there are 8 digits to the RIGHT of the decimal point, the exponent of 10 (always the second factor) is 8. 670,000,000 = 6.7 x 108 To take a number from scientific notation to standard form, 8.024 x 106 1. Write out the first factor. 8.024 2. Look at the exponent. Add zeros to the first factor until you have as many digits to the right of the decimal as your exponent. 8.024000 3. Erase the decimal point and put commas when appropriate. 8,024,000 18 Scientific Notation with Negative Exponents When changing a decimal number (with no whole number) from standard form to scientific notation, you must .00002405 1. Place a decimal in the number that will make a number greater than 1 but less than 10. Keep the original decimal. .00002.405 2. Count the number of digits in between the two decimals. This will be your exponent. 5 3. Erase the original decimal and all the zeros before your new decimal. This number will become your first factor. 2.405 4. All decimal numbers (really small numbers) will have negative exponents. Make your exponent negative. 2.405 x 105 When changing a number from scientific notation to standard form with a negative exponent, you must 1.259 x 107 1. Write out your first factor. 1.259 2. Add as many zeros to the left of the decimal as needed so there are as many digits as your exponent. 0000001.259 3. Put a new decimal on the left end of your number. Erase the old decimal. This is the number in standard form. .0000001259 19 Adding and Subtracting Integers When adding integers… When the signs are different: 1. Find the absolute value of each number 2. Find the difference between the numbers (subtract the absolute values) 3. For your answer, use the sign of the number with the greater absolute value Example: 6 3 6 3 3 -6 + 3 = Absolute value of -6 is 6 Absolute value of 3 is 3 6-3=3 the great absolute value is 6, it’s sign was negative Answer -3 When adding integers and the signs are the same, Keep the sign and add normally. Example: -7 + -4 = -11 or 2 + 3= 5 When subtracting integers, use K= Keep 1. 2. 3. 4. C=Change C=Change Keep the first integer the same. Change the subtraction sign to addition Change the sign of the last integer Then add using the rules of addition from above Example: -6 - (-9)= -6 Keep + Change 9= Change 3 20 Multiplying and Dividing Integers When multiplying integers, 1. Change any negative integers to positive integers 2. Multiply the integers normally 3. Find the sign this way: a. if the signs are the same then the product is positive b. if the signs are different, then the product is negative When dividing integers, 1. Change any negative integers to positive integers 2. Divide the integers normally 3. Find the quotient by: a. if the signs are the same, the quotient is positive b. if the signs are different the quotient is negative Example: SAME -9 x -7 = 63 24 3 8 DIFFERENT -9 x 7 = -63 24 8 3 Same signs = positive answer Different Signs = negative answer 21 Order of Operations P E MD AS Please Excuse My Dear Aunt Sally This acronym will help you remember the steps to solving a problem using the Order of Operations. First…… Second….. Third….. Fourth…. P= Parentheses E= Exponents MD= Multiplication and Division AS= Addition and Subtraction In the third and fourth steps (MD/AS), you complete these in order from left to right. 3 + 22(1+8) = P (1+8)=9 3 + 2 2 (9)= E 2 2 =4 3 + 4(9)= MD 4(9)=36 3 + 36= AS 3+36=39 39 A helpful tip is to actual write out P E MD AS next to each problem. As you complete each step of the Order of Operations, cross off the letter. This will allow you to keep track of what operation needs to happen next. 22 One Step Equations To solve one-step equations use the inverse operation. Addition is the inverse of subtraction, so subtraction is the inverse of addition. Multiplication is the inverse of division, so division is the inverse of multiplication. Step One: Identify the inverse operation Step Two: Get the variable (the letter) by itself Whatever you do to one side of the equation you MUST do to the other Addition x 4 11 Subtraction (inverse) - -4 = -4 X=7 (inverse) x 3 9 + +3 = +3 x = 12 Always check to make sure your answer is correct. Plug in each value for the original variable. X=7 7+4=11 11=11 x=12 12-3=9 9=9 Multiplication Division 7x = 49 7x = 49 7 7 X=7 x =7 7(7)=49 49=49 (Inverse) x 2 4 x (Inverse) 4 2 4 4 x x=8 x=8 8 2 4 2=2 23 Two Step Equations Solving a two step equation is very similar to solving a one step equation. Do the inverse operation for addition or subtraction first. Do the inverse operation of multiplication or division last. Another example: A more advanced two step equation would follow these steps. 10 m 2 4 24 Percents Percent mean “per hundred”. A percent is just a fraction. When we write the percent, we are just writing the numerator of the fraction (the percent) over 100. 100 will ALWAYS be the denominator of a percent fraction. Changing fractions to percents To change a fraction to a percent you must follow these steps. 1. Divide the numerator by the denominator (top by bottom). This is the same process as changing a fraction to a decimal. 2. Multiply by 100. Step 1 3 3 4 Step 2 .75 4 .75 x 100= 75% Changing percents to fractions To change a percent to a fraction follow these rules. 1. Percents are ALWAYS out of 100. Your denominator will ALWAYS be 100. 2. Your percent becomes your numerator. 47% = 47 100 Changing decimals to percents To change a decimal to a percent follow these rules. 1. Move your decimal point 2 places to the right. This is the same as multiplying by 100. .36 = .36 x 100= 36% 25 Changing percents to decimals To change a percent to a decimal you must follow these rules. 1. Start where the original decimals point is in the percent. 2. Move the decimal 2 places to the left. This is like dividing by 100. 96% = 96.0= 96/100= .96 Percent Proportions This is how you compare numbers and percents. It is important to remember that percents can be written as fractions and ratios can be written as fractions. We are comparing the part to whole ratio of percents and numbers. _PART_ WHOLE or is of -Tip- When you see of _____, whatever is after of will be your WHOLE number When you see is that will be your part. If it says what number or what percent, that will be your variable This usually works. Example 1 Find 70% of 90. Step 1 Set up % proportion 70 x 100 90 Step 2 Cross Multiply 100x 6300 Step 3 Solve 1 Step Equation (Divide each side by 100) 100 x 6300 26 x 63 Example 2 What number is 75% of 600? Step 1 Set up % proportion 75 x 100 600 Step 2 Cross Multiply 100x 45000 Step 3 Solve 1 Step Equation (by dividing) 100x 45000 x 450 Example 3 What percent of 250 is 25? Step 1 Set up % proportion x 25 100 250 Step 2 Cross multiply 250x 2500 Step 3 Solve 1 Step Equation (by dividing) 250x 2500 x 10 27 Percent of Change Percent of increase This is when the price goes UP. 1. SUBTRACT to find the amount of change 2. Solve a % proportion x amountofchange 100 originalamount Remember you are solving for a percent. 3. Cross multiply and divide to find the percent of increase. Example: The junior high school’s enrollment changed from 1200 to 1350 students. Find the percent of change in enrollment. Round to the nearest whole percent. 1. 1350 – 1200= 150 2. x 150 100 1200 3. x 12.5 Cross Multiply and Divide Rounded is 13% The increase in student enrollment is 13% 28 Percents of decrease This is when the price goes down. 1. Divide the new amount by the original amount. 2. Subtract 1 from the result. 3. Write the decimal as a percent. new 1100 percent of decrease old Example: Potatoes baked in the oven require 60 minutes to cook. A pressure cooker can do the same job in 20 minutes. Find the percent of change in cooking time. Round to the nearest whole percent. 1. 20 60 .333 2. .333 – 1= -.6666 3. -.666= -66.66 % 66.66% rounded = -67% The percent of decrease is 67% 29 When using percent of increase or decrease, you must first decide if it’s going up or down. UP = % of Increase Down = % of Decrease Sales Tax and Discounts Sales tax is a percent of the purchase price. We will continue using proportions to solve these problems. Tax _ or _ Discount % price 100 1. Set up the proportion 2. Cross Multiply 3. Divide to find the variable Example1: Find the total price of a $17.75 soccer ball if the sales tax is 6%. x 6 17.75 100 106.5 = 100x 1.065 = x Round 1.065 to $1.07 Now add the tax back to the original price to find the final total. $17.75 + 1.07 = $18.82 30 Example 2: Find the price of a $69.95 tennis racket that is on sale for 20% off x 20 69.95 100 1399 = 100x 13.99 = x Now subtract the 20% from the original price to find the discounted price. $69.95 -13.99 = $ 55.96 31 32 Sequencing There are 2 basic types of sequencing. Arithmetic Sequences An Arithmetic Sequence is made by adding the same value each time. 1, 4, 7, 10, 13, 16, 19, 22, 25, ... This sequence has a difference of 3 between each number. The pattern is continued by adding 3 to the last number each time. 3, 8, 13, 18, 23, 28, 33, 38, ... This sequence has a difference of 5 between each number. The pattern is continued by adding 5 to the last number each time. Geometric Sequences A Geometric Sequence is made by multiplying by the same value each time. 2, 4, 8, 16, 32, 64, 128, 256, ... This sequence has a factor of 2 between each number. The pattern is continued by multiplying the last number by 2 each time. 3, 9, 27, 81, 243, 729, 2187, ... This sequence has a factor of 3 between each number. The pattern is continued by multiplying the last number by 3 each time. 33 Finding Patterns When faced with a sequence, you need to look at it and see if you can get a "feel" for what is going on. Find the next number in the following sequence: 1, 4, 9, 16, 25,.... 12 = 1, 22 = 4, 32 = 9, 42 = 16, and 52 = 25. The next number in the sequence is 62 = 36. It looks as though the pattern here is squaring. That is, for the first term (the 1-st term), they squared 1; for the second term (the 2-nd term), they squared 2; for the third term (the 3-rd term), they squared 3; and so on. For the n-th term ("the enn-eth term"), they will want me to square n. In particular, for the sixth term, they will want me to square 6. Find the next number in the following sequence: 2, 5, 10, 17, 26,.... To find the pattern, I will list the numbers, and find the differences. That is, I will subtract the numbers in pairs (the first from the second, the second from the third, and so on), like this: The next term is 37. You would add 11 to 26 to find this number. really You may have to look hard to find the pattern. Don’t give up! It’ll appear. 34 Input/Output Tables Function machines such as the one below help students visualize how a rule associates each input value with an output value. Imagine a machine that works like this. When a number goes in (the input) it’s dropped into the machine. The machine changes the number according to the rule. Then a new number comes out (the output). For example: This machines rule is to add 5 to what is put in. Rule: f ( x) X + 5 So…….. if 4 goes in, 9 comes out. if 7 goes in, 12 comes out. If 53 goes in, 58 comes out. If -6 goes in, -1 comes out. These “in” and “out” numbers can be displayed in a table like this: Input 4 7 53 -6 Output 9 12 58 -1 35 To solve these types of problems you may need to find missing information for both inputs and outputs OR you may even need to find the rule. Let’s try an example problem: Rule: f ( x) x 7 Input 9 12 27 51 Output Rule: f ( x ) 3 x Input 3 Output 12 5 6 21 Rule: Input f ( x) x 5 Output 1 10 3 25 Rule: ? ____________________ Input 2 3 4 5 6 7 Output 1 1.5 2 2.5 3 3.5 36 Coordinate Plane The plane determined by a horizontal number line, called the x-axis, and a vertical number line, called the y-axis, intersecting at a point called the origin. Each point in the coordinate plane can be specified by an ordered pair of numbers. There are four quadrants in a coordinate plane. Labeled above. Points in Quadrant 1 have positive x and positive y coordinates. Points in Quadrant 2 have negative x but positive y coordinates. Points in Quadrant 3 have negative x and negative y coordinates. Points in Quadrant 4 have positive x but negative y coordinates. The center of the coordinate plane is called the origin. It has the coordinates of (0,0). 37 You can locate any point on the coordinate plane by an ordered pair of numbers (x,y) called the coordinates. Here the ordered pair is (2,3) The x value is 2 and the y value is 3. When an ordered pair is used to locate a point on a grid, the two numbers are called the 'coordinates' of the point. In the diagram above, the point (2, 3) has been marked with a dot. The coordinates of this point are '2' and '3'. 38 Slope and Y-Intercept Every straight line can be represented by an equation: y = mx + b. The coordinates of every point on the line will solve the equation if you substitute them in the equation for x and y. Slope = change in y change in x The steepness of a line is called its SLOPE. The vertical change is called the change in y. (Up and Down) The horizontal change is called the change in x. (Right and Left) We often refer to slope as… rise run Point Slope Form The slope of a line can also be found by using the coordinates of any two points on the line. Slope= difference in y-coordinates = y2 y1 x2 x1 Difference in x-coordinates For example: Find the slope of a line that contains the points A (-1, -2) and B (-4, -3). Slope = (-2) – (-3) (-1) – (-4) -2 + 3 or 1 3 -1 +4 When a line has positive slope, it rises from left to right. When a line has a negative slope, it falls from left to right. 39 The equation of any straight line, called a linear equation, can be written as: y = mx + b, where m is the slope of the line and b is the y-intercept. The y-intercept of this line is the value of y at the point where the line crosses the y axis. Remember Let's use these two points to calculate the slope m of this line. A = (1,1) and B = (2,3) Subtract the y value of point A from the y-value of point B to find the change in the y value, which is 2. Then subtract the x value of point A from the x value of point B to find the change in x, which is 1. The slope is 2 divided by 1, or 2. 40 Graphing Equations Remember… We compare the x-axis to a number line. If you move right from the origin, your x value will be a positive number. If you move left from the origin, your x value will be a negative number. We compare the y-axis to a thermometer. As you go up, the y value will be a positive number. As you go down the y value will be a negative number. Use this table as a reference x Move right (positive number) y Move up (positive number) Move left (negative number) Move down (negative number) …by plotting points on a coordinate plane The first thing you must do is to set up a function table like below. Use the “x” values of -3, 0, 3 for all tables unless otherwise given. x -3 0 3 y (x,y) Next you apply the Rule or Equation. For example: Y = 2x + 2 x -3 0 3 y -4 2 8 (x,y) (-3,4) (0,2) (3,8) The next step will be to plot these points on a coordinate graph and draw the line that contains them. 41 …by using slope and y intercept The point where a graph intersects an axis is called an INTERCEPT of the graph. The Y-INTERCEPT is the value of an equation when x= 0. For Example: To find the y-intercept let x = 0 y= x + 3 y=0+3 y=3 To graph lines you must know that: y = mx + b Where For example: y = m= slope b= y-intercept 2 x2 3 2 and Y-intercept (b)= (0,2) 3 On the graph you will: Slope (m) = 1. Plot y-intercept 2. Locate other points by using slope 3. Connect the points with a line 42 To graph a linear equation, we can use the slope and y-intercept 1. Locate the y-intercept on the graph and plot the point. 2. From this point, use the slope to find a second point and plot it. 3. Draw the line that connects the two points. 43 Solving Inequalities Solving linear inequalities is very similar to solving linear equations, except for one detail: you flip the inequality sign whenever you multiply or divide the inequality by a negative. The easiest way to show this is with some examples: 1) The only difference here is that you have a "less than" sign, instead of an "equals" sign. Note that the solution to a "less than, but not equal to" inequality is graphed with a parentheses (or else an open dot) at the endpoint. Graphically, the solution is: 2) Note that "x" does not have to be on the left, but it is often easier to picture how to deal with it this way. Don't be afraid to rearrange things to suit your taste. Graphically, the solution is: 3) Same ol', same ol', but with a "less than or equal to" sign, instead of a plain "equals". Note that the solution to a "less than or equal to" inequality is graphed with a bracket (or else a closed dot) at the endpoint. Graphically, the solution is: 44 4) Divide both sides by a positive two. Copyright © Elizabeth Stapel 2000-2007 All Rights Reserved Graphically, the solution is: 5) This is the special case noted before. When we divided by the negative two, we had to flip the inequality sig Graphically, the solution is: Look at these examples: 45 Simplifying Expressions Algebraic expressions contain alphabetic symbols as well as numbers. When an algebraic expression is simplified, an equivalent expression is found that is simpler than the original. This usually means that the simplified expression is smaller than the original. There is no standard procedure for simplifying all algebraic expressions because there are so many different kinds of expressions, but they can be grouped into three types: (a) those that can be simplified immediately without any preparation. (b) those that require preparation before being simplified. (c) those that cannot be simplified at all. Type A 2x + 3y - 2 + 3x + 6y + 7 This expression can be simplified by identifying like terms and then grouping and combining like terms, like this: · +2x and +3x are like terms, and can be combined to give +5x, · +3y and +6y combine to give +9y, and · -2 and +7 combine to give +5. So after simplifying, this expression becomes: 5x + 9y + 5 Type B Distribute into the parenthesis Combine like terms by adding coefficients and constants 46 47 Customary Unit Conversion Quantity measured Length Unit Symbol inch in foot yard mile ft yd mi Mass (“weight”)* ounce oz pound ton lb T Area square inch in² square foot square yard ft² yd² ounce oz cup pint quart c pt qt gallon g Volume Relationship 1 ft = 12 in 1 yd = 3 ft or 36 in 1 mi = 1760 yd or 5280 ft 1 lb = 16 oz 1 T = 2000 lb 1 ft² = 144 in² 1 yd² = 9 ft² 1 c = 8 oz 1 pt = 2 cups 1 qt = 2 pt 1 g = 4 qt In general, when you convert from a smaller unit to a larger one you will divide. 2r 8 8 2 32 12 12 32 2 2 ft Ex. 32 in = _______ ft 12 3 20 8 oz/c 2 c/pt 2 pt/qt Ex. 20 oz - _______ qt 20 1 1 1 20 5 or 0.625qt 1 8 2 2 32 8 **Remember that when dividing you may multiply by a number’s reciprocal-1 the reciprocal of n is . n ***Sometimes you must repeatedly divide or multiply a given amount to convert it to another unit of measurement. So, when you convert from a larger unit from a smaller unit you will multiply. Ex. 3 c = _______ oz 4 Ex. 2 qt = _______ c 3 16oz 48 12 oz 4 1c 4 2 2 pt/qt 2 c/pt = 8 c 48 Metric Unit Conversion Quantity measured Length, width, distance, thickness, girth, etc. Mass (“weight”)* Area Volume Unit Symbol Relationship millimeter mm 10 mm = 1 cm centimeter meter kilometer cm m km 100 cm = 1 m milligram mg gram kilogram metric ton g kg t 1 kg = 1000 g 1 t = 1000 kg square meter m² 1 m² = 10,000 cm² square kilometer km² 1 km² = 1,000,000 m² milliliter mL cubic centimeter liter cm³ L 1 km = 1000 m 1000 mg = 1 g 1000 mL = 1 L 1 cm³ = 1 mL 1000 L = 1 m³ The same general rules apply when converting between units in the metric system: you will be dividing when changing from a smaller unit to a larger one and multiplying when changing from a larger unit to a smaller one. **Remember here that you may use the shortcut of moving the decimal point to the right when multiplying or to the left when dividing. Ex. 135 cm = _______ m Ex. 0.75 kg = _______ mg 135 100 cm/m 1.35 m 0.75 1000 g/kg 1000 mg/g 750000 mg **You may also express your answer in scientific notation: 750000 7.5105 Ex. 1.5 L = _______ mL 1.5 1000 mL/L 1500mL 49 US Customary Length Weight 1 ft = 12 inch 1 yd = 3 ft 1 mi = 1760 yd 1 mi = 5280 ft Capacity 1 lb = 16 oz 1 T = 2000 lb 1 gal = 4 qt 1 gal = 8 pt 1 gal = 16 c 1 qt = 2 pt 1 qt = 4 c 1 pt = 2c 1 c = 8 fl oz When converting from a big unit to a small unit you multiply. When converting from a small unit to a big unit you divide. Metric Conversions Kangaroos Hop Down km hm dam kL hL daL kg hg dag Mountains Base Unit Meter (m) Liter (L) Gram (g) Drinking Chocolate Milk dm cm mm dL cL mL dg cg mg When going from a big unit to a small unit you move to the right, therefore you move your decimal the same amount of spaces to the right. When going from a small unit to a big unit you move to the left, therefore you move your decimal the same amount of spaces to the left. 50 Geometric Shapes A polygon is a closed figure made by joining line segments, where each line segment intersects exactly two others. Geometric Shape (polygon) Triangle (a) Equilateral (b) Isosceles (c) Scalene Quadrilateral (a) Trapezoid (b) Parallelogram (c) Rectangle (d) Square (e) Rhombus Description Diagram A closed three-sided figure All sides are congruent Two congruent sides No congruent sides (b) (a) A closed four-sided figure Two parallel sides Two pairs of parallel sides with the opposite sides having the same length A parallelogram with four right angles All sides are congruent with four right angles A parallelogram with all sides congruent (a) (c) (b) (e) (c) (d) Perimeter The perimeter of a polygon is the distance around the outside of the figure. To find the perimeter of triangles, quadrilaterals, or other polygons all you need to do is find the sum of the lengths of all the sides. Ex. Find the perimeter of the triangle. 10 in 6 in 6 8 10 24 in 8 in 7 cm Ex. Find the perimeter of the trapezoid 10 cm 7 10 10 16 43cm 10 cm 16 cm 51 Area The area of a polygon is the measure of the region inside the figure. It is the number of square units needed to cover its surface. To find the area of triangles, quadrilaterals, or other polygons is given by the general formula: A = b h , where A is the area; b = the length of the base; and h = the height of the figure. Ex. Find the area of the rectangle. 2m A=b h A = 6.2 2 A = 12.4m 2 6.2 m **Note that the formula for the area of a square is A = s 2 s Ex. Find the area of the triangle. **Note that if you draw a diagonal line from corner to corner, you will divide the rectangle into two congruent triangles. 2 cm 1 2 The formula for finding the area of a trapezoid is: A = 12 b1 b2 h A= A= A= b1 b 2 h 1 2 7 15 5 1 2 22 5 1 2 110 1 2 A= 1 2 b h 2 2 1 2 4 A = 2cm 2 b×h Ex. Find the area of the trapezoid. A= 1 2 A= 2 cm Therefore, the formula for the area of a triangle is A= A= 7 in 5 in 15 in A = 110 52 ***Circles radius diameter The diameter is a straight line passing through the center of a circle to touch both sides of the circumference. The radius is the distance from the center of a circle to its circumference. It is half the diameter The distance around the outside of a circle is called the circumference rather than the perimeter. The formula for finding the circumference of a circle is: C = 2 r or C = d The area of a circle is the measure of the region inside the circle. It is the number of square units needed to cover its surface. The formula for finding the area of a circle is: A = r2 In calculations, we will typically use the fraction 22 or the 7 decimal 3.14 for pi (). Ex. What is the circumference of a circle with a radius of 3 cm? C = 2 r C 2 3.14 3 C 2 9.42 **Note that you use the symbol because you C 18.84 cm are using an approximate value for pi . Ex. Find the area of a circle with a diameter of 6 ft. A = r2 6 A = 3.14 2 A A 2 3.14 3 3.14 9 2 **Remember that you need to divide the diameter by 2 to get the radius. 6 ft A 28.26ft 2 53 Surface Area Three-dimensional shapes can be solid or hollow. They have width, height and length. The surface area of a three-dimensional figure is the total area of the surface of a solid, including the area of the base(s) of the figure. That means that you will be finding the areas of all the surfaces of a threedimensional figure and adding them up. When using the formulas below you must remember that the width of a rectangle may be the same as the base of a triangle – so it may be helpful to redraw the three-dimensional shape in “pieces”. Three-dimensional Shape Rectangular Prisms h Surface Area Formula SA = 2lw +2lh +2wh If you have a cube the formula for surface area is: SA = 6s2 w l Triangular Prisms SA = area of 2 triangular bases + the areas of the rectangular sides Pyramids SA = the area of the base (whatever shape) + the area of the faces or sides Cylinders radius SA = 2 r 2 2 r h 54 SA = r 2 + rs where s = the slant height of the curved surface Cones s r Ex. Find the surface area of a rectangular prism with a length or 5 in, width of 2 in and height of 4 in. 4 in SA = 2lw +2lh +2wh 2 in 5 in SA = 2 5 2 2 5 4 2 2 4 SA = 2 10 2 20 2 8 SA = 20 +40+16 SA = 76 in 2 Ex. Find the surface area of the triangular prism. SA = area of 2 triangular bases + the areas of the rectangular sides SA = 2 bh 2 lw two congruent sides lw third side 1 2 5 mm 4 mm 15 mm 6 mm SA = 6 5 2 15 4 15 6 SA = 30 + 2 60 80 SA = 30 + 120 + 80 SA = 230 mm 2 Ex. Find the surface area of the pyramid. 6 cm SA = the area of the base (whatever shape) + the area of the faces or sides SA = s 2 4 12 bh SA = 5 4 12 5 6 5 cm 2 SA = 25 + 4 30 SA = 25 + 4 15 5 cm 1 2 SA = 25 + 60 SA = 85 cm 2 Ex. Find the surface area of a cylinder with a diameter of 3 in and a height of 6 in. SA = 2 r 2 2 r h SA = 2 1.5 2 1.5 6 SA 2 3.14 2.25 2 3.14 6 3 in 2 SA 14.13 37.68 SA 51.81in 2 6 in 55 **Remember that you need to divide the diameter by 2 to get the radius. Ex. Find the surface area of a cone with a radius of 4 in and slant height of 7 in. SA = r 2 + rs SA = 4 4×7 4 in 7 in 2 SA 3.14 16 3.14 28 SA 50.24 + 87.92 SA 138.16 in 2 56 Volume The general formula for finding the volume of a three-dimensional figure is: V = Bh, where B is the area of the base Three-dimensional Shape Rectangular Prisms Volume Formula V = lwh h w l Triangular Prisms V = 12 lwh Pyramids V = 13 Bh B = the area of the base which may be a rectangle, triangle, or other shape Cylinders V = r 2h radius h Cones V = 13 r 2h h r Ex. Find the volume of a rectangular prism with a length or 5 in, width of 2 in and height of 4 in. V lwh V 5 24 4 in 5 in 2 in V 40 in 3 57 Ex. Find the volume of the triangular prism. V 12 lwh 6 4 15 V 12 360 V 5 mm 1 2 4 mm 15 mm 6 mm V 180 mm 3 Ex. Find the volume of the pyramid. V 13 Bh 5 5 7 V 13 175 V 1 3 7 cm 5 cm V 58.333 mm 3 V 58.3 mm 5 cm 3 Ex. Find the volume of a cylinder with a diameter of 3 in and a height of 6 in. V 13 Bh **Remember that you need to divide the diameter by 2 to get the radius. V r 2h 3 in 6 in V 3.141.5 h 2 V 3.142.25 6 V 42.39 mm 3 Ex. Find the surface area of a cone with a radius of 4 in and height of 6 in. V 13 r 2h V 1 3 3.141.5 6 2 4 in 6 in 3.142.25 6 2 3 V 14.13 mm 3 V 58 Scale Factor/Proportions Scale drawings are the same shape but not the same size as the objects they represent. The scale factor is a ratio that shows how much the drawing has been magnified or reduced. Indirect measurement is a method used to calculate the measurement of extremely large or hard to measure objects such as a tree, building or mountain; using a proportion. Ex. The height of the person is 6 ft tall and his shadow has a length of 2 ft. If a tree has a shadow that measures 6ft, we can determine the tree's height with this proportion: man's shadow man's height = tree's shadow tree's height 2 6 = = 2h = 36 6 h h = 18 ft 59 Types of Triangles In the earlier section on polygons we discussed how triangles are classified according to the lengths of their sides. Triangles may also be classified according to what kind of angles they contain. Description All angles are less than 90o Triangle Name Acute Triangle All angles are 60c Example Equiangular 60o 60o One angle is greater than 90c One angle is exactly 90c 60o Obtuse Right Ex. 60o 60 Ex. o This triangle may be classified as obtuse triangle and also as an isosceles triangle. This triangle may be classified as a right triangle and also as a scalene triangle. 60 Pythagorean Theorem In any right triangle, the area of the square whose side is the hypotenuse (the side of a right triangle opposite the right angle) is equal to the sum of areas of the squares whose sides are the two legs (i.e. the two sides other than the hypotenuse). If we let c be the length of the hypotenuse and a and b be the lengths of the other two sides, the theorem can be expressed as the equation: a 2 b2 c 2 The side of the triangle opposite the right angle (c) is the hypotenuse. The other sides are called legs (a) and (b). hypotenuse leg a c b leg A = c2 A = a2 a b c A = b2 61 Ex. The Pythagorean Theorem may be used to find the height of a ladder leaning against a wall. If the bottom of an 11 m ladder is placed 4 m from a wall and leaned in, how far up the wall does the ladder reach? a 2 b2 c 2 42 x 2 112 16 x 2 121 16 16 x 2 121 16 x 2 105 x 2 105 x 10.25 m Ex. What is the diagonal length of a TV screen whose dimensions are 80 x 60 cm? a 2 b2 c 2 602 802 x 2 3600 6400 x 2 10, 000 x 2 10, 000 x 2 100 cm x 62 Translation, Rotation, Reflection, Dilation There are four different kind of transformation. Remember that a transformation is a change in position or size. The four transformation are: rotation, translation, reflection, and dilation. Rotation is turning of a figure in certain direction and angle around the fixed point. Rotation Translation can be thought of as a slide of a figure in a plane. Translation 63 Reflection is like a mirror image. Reflection Dilation is when you enlarge or shrink a figure. Dilation 64 65 Measures of Central Tendency Mean- the average of a set of data Median- the middle number of a set of data Mode- The number that appears the most in the set of data Range- The difference between the highest and lowest numbers in a set of data Upper Quartile- the median of the upper half of numbers in the set of data Lower Quartile- the median on the lower half of the set of data REMEMBER!! WHEN CALCULATING MEDIAN (AND QUARTILES) IF YOU HAVE TWO NUMBERS ADD TOGETHER AND DIVIDE BY 2 66 Scatterplots Statisticians and quality control technicians gather data to determine correlations (relationships) between events. Scatter plots will often show at a glance whether a relationship exists between two sets of data. Do you think the amount of time Regent would spend studying will affect his grade? Let's decide if studying longer will effect Regent’s grades based upon a specific set of data. Given the data below, a scatter plot has been prepared to represent the data. Remember when making a scatter plot, do NOT connect the dots. Study Hours 3 5 2 6 7 1 2 7 1 7 Regents Score 80 90 75 80 90 50 65 85 40 100 The data displayed on the graph resembles a line rising from left to right. Since the slope of the line is positive, there is a positive correlation between the two sets of data. This means that according to this set of data, the longer he studies, the better grade Regent will get on his examination. If the slope of the line had been negative (falling from left to right), a negative correlation would exist. Under a negative correlation, the longer Regent studies, the worse grade he would get on his examination. YEEK!! If the plot on the graph is scattered in such a way that it does not approximate a line (it does not appear to rise or fall), there is no correlation between the sets of data. No correlation means that the data just doesn't show if studying longer has any affect on Regent’s examination scores. 67 Histogram A histogram is a graphical method for displaying the shape of a distribution. It is particularly useful when there are a large number of observations. The first step is to create a frequency table. The left side is the intervals and the right side is the frequency or how often the event occurs in that interval. Here is a set of data: 8, 12, 13, 19, 21, 22, 25, 27, 27, 29, 33, 36, 38, 39, 44, 48 Data Range Frequency 0-10 1 10-20 3 20-30 6 30-40 4 40-50 2 **Sometimes tally marks are used to count frequency** Then create a histogram by having the frequency on the y axis and the intervals of data on the x axis. 68 Box and Whisker Plots Vocabulary Box and Whisker Plot – A way to display and summarize data. Upper Quartile – The median of the upper half of numbers from the set of data. Lower Quartile - The median of the lower half of numbers from the set of data. Upper Extreme – The highest number in the set of data that is not an outlier. Lower Extreme – The lowest number in the set of data that is not an outlier. Interquartile range – The value achieved by subtracting the upper quartile and the lower quartile. Outlier – A number that is more than 1.5 times the interquatile range from the upper or lower quartiles. Median – the middle number from the set of data. The first step in constructing a box-and-whisker plot is to first find the median, the lower quartile and the upper quartile of a given set of data. Example: The following set of numbers are the amount of marbles fifteen different boys own (they are arranged from least to greatest). 18 27 34 52 54 59 61 68 78 82 85 87 91 93 100 68 is the median; 52 is the lower quartile; 87 is the upper quartile Now you would construct your box and whisker plot. 69 Step by Step instructions on making a box and whiskers plot We know that the median of a set of data separates the data into two equal parts. Data can be further separated into quartiles. The first quartile is the median of the lower part of the data. The second quartile is another name for the median of the entire set of data. The third quartile is the median of the upper part of the data. Quartiles separate the original set of data into four equal parts. Each of these parts contains one-fourth of the data. The data: Math test scores 80, 75, 90, 95, 65, 65, 80, 85, 70, 100 Write the data in numerical order and find the first quartile, the median, the third quartile, the smallest value and the largest value. median = 80 first quartile = 70 third quartile = 90 smallest value = 65 largest value = 100 Place a circle beneath each of these values on a number line. Draw a box with ends through the points for the first and third quartiles. Then draw a vertical line through the box at the median point. Now, draw the whiskers (or lines) from each end of the box to the smallest and largest values. 70 Stem and Leaf Plot A stem-and-leaf plot is a display that organizes data to show its shape and distribution. In a stem-and-leaf plot each data value is split into a "stem" and a "leaf". The "leaf" is usually the last digit of the number and the other digits to the left of the "leaf" form the "stem". The number 123 would be split as: stem leaf 12 3 Constructing a stem-and-leaf plot: The data: Math test scores out of 50 points: 35, 36, 38, 40, 42, 42, 44, 45, 45, 47, 48, 49, 50, 50, 50. Writing the data in numerical order may help to organize the 35, 36, 38, 40, 42, 42, 44, 45, 45, 47, 48, 49, 50, data, but is NOT a required 50, 50 step. Ordering can be done later. Separate each number into a The number 38 would be represented as stem and a leaf. Since these are two digit numbers, the tens digit Stem Leaf is the stem and the units digit is 3 8 the leaf. Group the numbers with the Math Test Scores same stems. List the stems in (out of 50 pts) Stem Leaf numerical order. (If your leaf 3 568 values are not in increasing 4 022455 789 order, order them now.) Title 5 000 the graph. Prepare an appropriate legend Legend: 3 | 6 means 36 (key) for the graph. A stem-and-leaf plot shows the shape and distribution of data. It can be clearly seen in the diagram above that the data clusters around the row with a stem of 4. 71 Notes: The leaf is the digit in the place farthest to the right in the number, and the stem is the digit, or digits, in the number that remain when the leaf is dropped. To show a one-digit number (such as 9) using a stem-and-leaf plot, use a stem of 0 and a leaf of 9. To find the median in a stem-and-leaf plot, count off half the total number of leaves. Special Case: If you are comparing two sets of data, you can use a back-to-back stemand-leaf plot. Data Set A Leaf 320 Stem 4 Data Set B Leaf 1567 The numbers 40, 42, and 43 are from Data Set A. The numbers 41, 45, 46, and 47 are from Data Set B. 72 Bar Graph Bar graphs are the simplest way to display data. Remember: Bar graphs display data. When making a bar graph, be sure to include all the correct parts. First, draw the x and y axis. Next, number the scale. axis axis 3 2 scale 1 Then, label the x and y axis. After that, give the bar graph a title. axis axis label label 3 2 3 1 2 1 TITLE scale scale label label 73 Finally, draw the bars using your data. axis label Your finished bar graph should look like this. TITLE 3 2 bars 1 scale label 74 Circle Graphs Circle graphs, also called pie charts, are a type of graph used to represent a part to whole relationship. They are circular shaped graphs with the entire circle representing the whole. The circle is then split into parts, or sectors. Each sector represents a part of the whole. Each sector is proportional in size to the amount each sector represents, therefore it is easy to make generalizations and comparisons. Circle graphs represent 100% 75 Probability Definition Example An experiment is a situation involving chance or probability that leads to results called outcomes. In the problem below, the experiment is spinning the spinner. An outcome is the result of a single trial of an experiment. The possible outcomes are landing on yellow, blue, green or red. An event is one or more outcomes of an experiment. One event of this experiment is landing on blue. Probability is the measure of how likely an The probability of landing on blue is one fourth. event is. Experiment 1: A spinner has 4 equal sectors colored yellow, blue, green and red. After spinning the spinner, what is the probability of landing on each color? Outcomes: The possible outcomes of this experiment are yellow, blue, green, and red. Probabilities: P(yellow) = number of ways to land on yellow 1 = total number of colors 4 = number of ways to land on blue 1 = total number of colors 4 P(green) = number of ways to land on green 1 = total number of colors 4 P(blue) P(red) = number of ways to land on red 1 = total number of colors 4 76 Theoretical Probability Theoretical probability is the ratio of the number of ways the event can occur to the total number of possibilities in the sample space. The theoretical probability of an event is based on the assumption that each of a number of possible outcomes is equally likely. The theoretical probability of an event can be defined as the ratio of the number of favorable outcomes to the total number of outcomes in the sample space. For example, if a die is tossed, the probability of getting a 4 is because 4 is one of six possible outcomes. Similarly, the probability of getting a number less than 5 is , because either 1, 2, 3, or 4 is favorable. Experimental Probability The experimental probability for equally likely events is the fraction: # favourable outcomes total outcomes If you toss a coin 50 times and you end up with 20 heads and 30 tails, the experimental probability is: P(H) = 20/50 = 0.4 P(T) = 30/50 = 0.6 Theoretical experiment changes from experiment to experiment. If the experiment is fair, the theoretical and experimental probability should be very similar if a large number of trials are made. Try flipping a coin yourself. Flip it 50 times and record the numbers of heads and tails. Divide your totals by 50 to get the experimental probability. 77 Difference between experimental and theoretical probability Think about tossing a coin. You should get a head or a tail 50% or ½ of the time. This is the theory or theoretical probability. If you actually toss a coin 20 times will your probability be ½? The theoretical probability of the The experimental probability for equally event is the fraction: likely events is the fraction: # ways the event can occur total possible outcomes # favourable outcomes total outcomes In the Experiment, the theoretical The experimental probability for equally probability of the event that heads likely events is the fraction: comes up is: # favourable outcomes P(H) 1/2 = 0.5 = 50% total outcomes = P(T) 1/2 = 0.5 = 50% In the Experiment, if heads comes up 13 of = 20 times, the experimental probability of the event that heads comes up is: P(H) = 13/100 = 0.65 = 65% Think about this: The more times you complete an experiment, the closer it’s probability should come to being the same as the theoretical probability. 78 Tree Diagram When attempting to determine a sample space (the possible outcomes from an experiment), it is often helpful to draw a diagram which illustrates how to arrive at the answer. One such diagram is a tree diagram. In addition to helping determine the number of outcomes in a sample space, the tree diagram can be used to determine the probability of individual outcomes within the sample space. The probability of any outcome in the sample space is the product (multiply) of all possibilities along the path that represents that outcome on the tree diagram Show the sample space for tossing one penny and rolling one die. (H = heads, T = tails) By following the different paths in the tree diagram, we can arrive at the sample space. Sample space: { H1, H2, H3, H4, H5, H6, T1, T2, T3, T4, T5, T6 } The probability of each of these outcomes is 1/2 • 1/6 = 1/12 A family has three children. How many outcomes are in the sample space that indicate the sex of the children? Assume that the probability of male (M) and the probability of female (F) are each 1/2. Sample space: { MMM MMF MFM MFF FMM FMF FFM FFF } There are 8 outcomes in the sample space. The probability of each outcome is 1/2 • 1/2 • 1/2 = 1/8. 79 Simple Probability Probabilities are numbers expressed as ratios, fractions, decimals, or percents. They are determined by considering the results of an experiment. Simple probability is when we conduct a one stage or one object experiment. We choose an event, then the probability of that event is found by counting the number of times the event is true (favorable) and dividing by the total number of possible and equally likely outcomes. P(event) = number of true outcomes total number of equally likely outcomes COIN A common example is tossing a fair coin. There are two possible outcomes in the sample space S = {heads, tails}. The probability of event A = "tossing a head" is found by considering the number of true outcomes (head) divided by the number of possible outcomes (head/tail), or 1/2. Notice that probability of tossing a tail is also 1/2. We denote this as P(H) = 1/2 or P(T) = 1/2. We can describe several probabilities using a spinner numbered with eight equal sections (so there are equally likely outcomes). Here the sample space is S = {1,2,3,4,5,6,7,8}. P(5) = 1/8 The probability of spinning a five is one out of eight P(even) = 4/8 The probability of spinning an even number is four out of eight P(~ 3) = 7/8 The probability of spinning anything but three is seven out of eight P(> 2) = 6/8 The probability of spinning a number greater than two is six out of eight P(10) =0 SPINNER Spinning a ten is an impossible event P(<10) = 8/8 Spinning a number less than ten is eight out of eight is certain DICE The probability of rolling a specific number on one fair die is 1/6. However, we also consider the probability of rolling a two or a six. We use the addition rule to add the probability of rolling a two (1/6) and the probability of rolling a six (1/6) to get the total probability P(2 or 6) = P(2) + P(6) = 2/6. 80 Compound Probability The theory that the probability that two independent events will occur is equal to the probability that one independent event will occur times the probability that a second Independent event will occur. For example, on a single toss of two dimes (each dime having a head and a tail), the probability that both will land on their tails is equal to 1/4 (1/2 x 1/2). A compound event involves the use of two or more items such as: two cards being drawn three coins being tossed two dice being rolled four people being chosen Amy has 5 tank tops, 3 pairs of jeans, and 2 pairs of sneakers. How many different outfits consisting of one tank top, one pair of jeans, and one pair of sneakers are possible? Counting Principle : 5 x 3 x 2 = 30 outfits How many different 4 letter words can be formed from the letters in the word MATH? Using Permutations: 4P4 = 4 • 3 • 2 • 1 = 24 81 82 Absolute value - The absolute value of an integer is its distance from 0 on a number line. The absolute value of n is written as |n|. Adjacent - Adjacent means 'next to'. Adjacent angles are immediately next to each other and share a common side. Adjacent sides are also immediately next to each other and share a common vertex. Box & Whisker Plot - A box-and-whiskerplot divides a data set into four parts: the lower quartile, which is the median of the lower half of the data the upper quartile, which is the median of the upper half of the data the lower extreme is the least value the upper extreme is the greatest value Algebraic expression - Algebraic expressions are combinations of variables, numbers, and at least one operation. Altitude - The altitude is the perpendicular distance from the vertex of a triangle to the opposite side. A Chord – A straight line joining two points on the circumference of a circle. Chord Arc Arc – An arc is part of a circle or curve between two points. B Circle graph – Also known as a pie chart or graph displays data as parts of circle. Area -- The measure of the region inside a figure. It is the number of square units needed to cover its surface. Arithmetic - An area of mathematics that includes: addition/subtraction/multiplication and division of whole number, decimals and fractions. Associative Property – Also known as the Grouping Property, changing the grouping does not change the result of the operation. Addition (a + b) +c = a + (b + c) Multiplication (ab)c = a(bc) Circumference – The distance around a circle is called the circumference. Bar Graph – A graph in which information is shown using columns or bars. Bar graphs make it easy to compare data.. Sales Coefficient – In a mathematical expression, it is the number that multiplies the variable(s). Ex. In 3x 2 5 y , 3 is the coefficient of x 2 term and 5 is the coefficient of the y term. 100 80 60 East 40 West 20 North Combination – An arrangement, or listing, of objects in which order is not important is called a combination. You can find the number of combinations of objects by 0 1st Qtr 2nd 3rd Qtr4th Qtr Qtr A 83 B dividing the number of permutations of the entire set by the number of ways each smaller set can be arranged. Commutative Property – Also known as the Order Property, changing the order of the numbers does not change the result of the operation. Addition a+b=b+a Multiplication ab = ba Complementary angle – One of two angles whose sum is 90o. Compound events – A compound event involves the use of two or more items such as: two cards being drawn three coins being tossed two dice being rolled four people being chosen a c then ad bc. b d 5 20 if , then 5 48 12 20. 240 = 240. 12 48 if Cross simplifying – The process of dividing out common factors diagonally across two ratios. Ex. If 17 h 17 h 1 h , then 35 102 35 102 35 6 Cubic/cubed – to be raised to the third power. n3 Degrees – 1) A unit for measuring the size of angles. 2) A unit for measuring temperature. Dependent event – If the result of one event affects the result of a second event, the events are called dependent events. Congruent – Two objects are congruent if they have the same shape and the same size. Diagonal – A diagonal is a line joining two non-adjacent vertices (corners) of a polygon. Conversion/convert – To change into another form, such as converting a mixed number to an improper fraction or converting a fraction to a decimal. Diameter – The diameter is a straight line passing through the center of a circle to touch both sides of the circumference. 1 2 Ex. 1 3 2 3 0.75 4 Coordinate grid – Also known as the coordinate plane, see below. Coordinate system/Coordinate plane – A coordinate system has a horizontal number line (called the x-axis) and a vertical number line (called the y-axis). These lines cross at right angles at a point called the origin (0, 0). Cross multiplying – [Cross Product Property]. The process of multiplying diagonally across two ratios. Distributive Property – The property of distributing one operation over another and the resulting answer is the same. a(b+c) = ab + ac 5(2 + 7) = (5 2) + (5 7) Divisible – One number is divisible by another number if the second number divides "evenly" into the first. That is, when the first number is divided by the second number, there is a remainder of zero. Domain – The set of xcoordinates of the set of 84 Factoring (polynomial) – Writing a polynomial as the product of monomials and/or polynomials. points on a graph; the set of x-coordinates of a given set of ordered pairs. The value that is the input in a function or relation. Ex. 2 x 2 4 x 6 2 ( x 2 2 x 3) Ex. The set of ordered pairs for the relation is {(2, 3), (3, 2), (4, 2), (0, 0)}. The domain is the first number of the ordered pairs {2, 3, 4, 0}. Factors – When two or more integers are multiplied, each integer is a factor of the product. "To factor" means to write the number or term as a product of its factors. Elimination –To remove a term (an unknown quantity) by combining like terms. Ex. 18 1 18; 18 2 9; 18 3 6. 1, 2, 3, 6, 9 and18 are factors. Equivalent – 1. equal in value, measure, force, effect, significance, etc. 2. Mathematics (of two sets) able to be placed in one-to-one correspondence. 3. Geometry having the same extent, as a triangle and a square of equal area. Formula – A formula is a mathematical rule written using symbols, usually as an equation describing a certain relationship between quantities. Event -- an experiment, an event is the Frequency – The number of times a particular item appears in a set of data is the frequency. result that we are interested in. Function – A function is a relation in which each element in the domain is paired with exactly one element in the range. Experimental probability – The experimental probability of an event is the estimated probability based on the number of positive outcomes in an experiment. Fundamental Counting Principle – also called the Basic counting principle is used to determine the number of outcomes for an experiment. The number of ways each choice can be made are multiplied together. Ex. Exponent – An exponent is a small number placed to the upper-right of a number showing the number of times that number is multiplied by itself. Exterior angles – 1) the angle formed outside a polygon when one side is extended. Angles 1 and 2 are exterior angles Home 2 1 Movie Theater House 2) an angle outside two lines when they are crossed by a third line (a transversal). Angles 1, 2, 7 and 8 are exterior angles. 2 paths to my friend’s house times 3 paths to the movie theater equals 6 different ways to walk to the movie theater. 2 3 6 t 1 3 5 7 My Friend’s 6 8 2 l 4 Height (altitude of a triangle) – the perpendicular distance from altitude or height m 85 the vertex of a triangle to the opposite side. Histogram – A histogram is a bar graph representing frequency distribution. Hypotenuse – The longest side of a right triangle is called the hypotenuse. Identity Property – (1) For addition, the identity number is 0 because 0 added to any number is that number. (2) For multiplication, the identity number is 1 because any number times 1 is that number. Interquartile range – The interquartile range is calculated by subtracting the lower quartile from the upper quartile. Interior angles – 1) an angle within a polygon. 2) An angle within two lines when they are crossed by a third line (a transversal). Intersecting lines – Lines that have one and only one point in common. Ex. a 0 a or 0 a a a 1 a or 1 a a Independent event – If the result of one event is not affected by the result of another event, the events are called independent events. Inequality – (1) not equal in size, amount or value. (2) A statement showing that one quantity is not equal to another. a < b means a is less tha b a a > b means a is greater that b a b means a is not equal to b Integer – An integer is any number from the set {… , -3, -2, -1, 0, +1, +2, +3, …}. Intercepts – An intercept is the point where the graph of an equation crosses an axis AB intersects PQ at point C Inverse operations – Inverse operations are “opposite” operations. They are used to solve equations and inequalities. addition and subtraction are inverse operations multiplication and division are inverse operations Irrational number – A real number that can be written as a non-repeating or nonterminating decimal, but not as a fraction is an irrational number. Isolation – the complete separation of the variable term(s) from the other terms in an equation. Levels of symmetry [lines of symmetry] – The line of symmetry is the line that divides the figure into two mirror images. Ex. In this example, 2 is the x-intercept and 2 is the y-intercept. 86 Linear – relating to a line Line graph – uses lines to join points which represent data Mode – In a set of data, the mode is the piece of data that occurs the most. Monomials – A monomial is a polynomial containing one term which may be a number, a variable or a product of numbers and variables, with no negative or fractional exponents. Negative numbers – Integers less than 0 are negative numbers. They are the opposites of the whole numbers. Non-linear – Not in a straight line. Lowest terms – Also called Simplest Form of a fraction. In a fraction, the numerator and denominator are relatively prime, meaning that they save no common factor other than 1. Ex. 1 is in lowest terms. 2 6 6 2 3 is not in lowest terms, and must be reduced. 8 8 2 4 Mass – Mass is the quantity of matter in an object. Mean – The mean of a data set is the arithmetic average. To find the mean, add all of the numbers in the data set and then divide by the number of items in the set. Measures of center (measures of central tendency) – The three most common measures of the center r middle of a distribution are the mean, median and mode. Median – The median is the middle number in a data set when the data are arranged in numerical order. When there is an even number of items in a data set, the median is the mean of the two middle numbers. Metric unit – The basic units of measurement in the metric system are: meter (m) for length; gram (g) for mass and liter (L) for capacity. Order of operations [PEMDAS] – 1. Do all operations within grouping symbols first. 2. Multiply and divide in order from left to right. 3. Add and subtract in order from left to right. Ordered pair – The first number in an ordered pair is the x-coordinate. It tells how far the point is to the right or left of the origin. The second number in an ordered pair is the y-coordinate. It tells how far the point is up or down from the origin. Origin – The point where the x-axis and yaxis meet. Outcome – An outcome is one of the possible results of a probability experiment. Outliers – An outlier is a value far away from most of the rest in a set of data.. Data that are more than 1.5 times the interquartile range from the quartiles are outliers. The limits on outliers are the points beyond which data are considered to be outliers. Parallel – Parallel lines are lines that are always the same distance apart. They never intersect (like railroad tracks). Percent – A permutation is an arrangement, or listing, of objects in which order is important. 87 Perimeter – The distance around the outside of a figure. Permutations – An arrangement of objects in particular order Quadrants – Any of the quarters of a coordinate plane are called quadrants. Perpendicular – Intersecting at or forming right angles. Pi – Pi () is the ratio of the circumference of a circle to its diameter. Polygon -- A closed figure made by joining line segments, where each line segment intersects exactly two others. Polynomials – The prefix poly means many--a polynomial is an expression that contains many terms. It is an expression that can be a monomial of the sum of monomials. Radius – The radius is the distance from the center of a circle to its circumference. It is half the diameter diameter radius Range – 1) The range of the data is the difference between the greatest and least numbers in the data. 2) The range of a function is the set of second numbers. Prime number – A counting number that has exactly two factors, itself and 1. Ex. The set of ordered pairs for the relation is {(2, 3), (3, 2), (4, 2), (0, 0)}. The range is {3, 2, 0}. Prime factor – A factor which is a prime number is called a prime factor. Prime factorization – Expressing a number as a product of prime factors. Rate – A rate is a ratio of two measurements with different units. Ex. 180 2 2 3 3 5 or 180=22 32 5 Rate of change – A change in one quantity with respect to another quantity is called a rate of change. Probability – Probability is the chance that a particular outcome will occur. Ratio – A ratio is a comparison of two numbers by division. Proportion – 1) A proportion is a part to whole comparison. 2) A proportion also states the equality of two ratios written as an equation. Rational number – A rational number is a real number that can be written as: a ratio of two integers, excluding zero as a denominator; a repeating or terminating decimal; or an integer. Pythagorean Theorem – In a right triangle, the sum of the squares of the lengths of the legs (a and b) is equal to the square of the length of the hypotenuse (c). a2 + b2 = c2, where a and b are the legs and c is the hypotenuse. c Real numbers – All numbers, rational and irrational make up the set of real numbers. Reduce – 1) make smaller in size or number 2) to simplify a fraction by dividing the numerator and denominator by its greatest common factor (GCF). a 88 b Reflection – A reflection is a mirror image of a figure across a line of symmetry. congruent and their corresponding sides are in proportion. Relation – A relation is a set of ordered pairs. The set of the first coordinates is the domain of the relation. The set of second coordinates is the range of the relation. You can model a relation with a table or graph. Similar figures – Objects or figures that have the same shape. They do not necessarily have the same size. Ex. Right angle – A right angle is one whose measure is exactly 90o. Rotation – 1) to turn an object 2) one of three basic rigid motions og geometry Sample – A sample is a section of a whole group. To get data from part of a group and use it to give information about the whole group. Scale – 1 an instrument with graduated spaces, as for measuring. (2) a graduated line, as on a map, representing proportionate size. (3) the proportion that a representation of an object bears to the object itself. Scatter plots – Graphs that show the relationship between two quantities. Ex. ABC DEF Simple event – or single event involves the use of ONE item such as: one card being drawn one coin being tossed one die being rolled one person being chosen Simplify – to make less complex or complicated; make plainer or easier. Simplest form – A fraction is in simplest form when the GCF of the numerator and denominator is 1. Skew lines – Lines that do not lie in the same plane in space, so that they cannot be parallel or intersect. Slope – The steepness of a line. Given by the ratio of the y-coordinates over the xcoordinates. This ratios is sometimes called rise-over-run. y y m 2 1 x2 x1 Square number – The square of a number is product of a number times itself. Similar polygons – Two polygons are similar if their corresponding angles are n2 n n 89 Square root – A number when multiplied by itself gives the original number. Standard unit – (1) In the English or customary system: mass = pound, length = feet, and volume = gallon. (2) In the metric system: mass = gram, length = meter, and volume = liter. Statistics – 1) Statistics is the collection, organization, presentation, interpretation and analysis of data. 2) A statistic is a single number, computed from a sample that summarizes some characteristic of a population. Stem & leaf plot – In a stem-and-leaf plot, the last digit in each data item is the leaf. The digits in front of the leaf become the stem. Ex. Systems of inequalities – or Simultaneous inequalities are two or more inequalities in two or more variables that are considered together or simultaneously. The system may or may not have common solutions. Terms – 1) one of the numbers in a sequence, e.g. 1, 3, 5, 7, … 2) one of the numbers in a series, e.g. 2 + 4 + 6 + 8… 3) one part of an algebraic expression which may be a number, a variable or a product of both. Tessellation – A tessellation is a repetitive pattern of regular polygons that fit together with no overlaps or gaps. In a tessellation, the sum of the measures of the angles where the vertices of the polygons meet is 360°. Theoretical probability – Theoretical probability is the ratio of the number of ways an event can occur to the total number of possible outcomes. Transformation – A change in position or size, including: reflection, translation, rotation, or dilation/enlargement. Substitution – an event in which one thing is substituted for another; such as replacing a variable in an expression with a number. Translation – A translation is sliding part of a drawing to another place without turning it. Supplementary angle – One of two angles whose sum is 180o. Transversal – A line (t) that intersects tow or more lines ( m and n) at different points. Surface area – The total area of the surface of a solid, including the area of the base(s) of the figure. Systems of equations – or Simultaneous equations are two or more equations in two or more variables considered together or simultaneously. A system of equations may have no common solution, one common solution, or an infinite number of common solutions. t m n Tree diagram – A diagram shaped like a tree used to display sample space by using one branch for each possible outcome. 90 Unit rate – A unit rate is a rate in which the denominator is 1 unit. Volume - The volume of a solid figure is the measure of the space it occupies Variable – Variables, usually letters, are used to represent numbers in some expressions. Vertical angles – A pair of angles directly opposite each other, formed by the intersection of straight lines. Vertical angles are congruent. Angles 1 and 4; 2 and 3; 5 and 8; and 6 and 7 are vertical angles. t 1 3 5 7 6 2 l 4 m 8 91 92 Websites that are useful for looking up information The Math Forum http://mathforum.org/dr.math/ WebMath http://www.webmath.com/ Math.com http://www.math.com/ Free Math Help http://www.freemathhelp.com/ Math League http://www.mathleague.com/help/help.htm Algebra Help http://www.algebra.com/ S.O.S Mathematics http://www.sosmath.com/ A+ Math http://www.aplusmath.com/ About.com http://math.about.com/ Purple Math http://www.purplemath.com/ Online Math Help http://www.onlinemathlearning.com/ Math Nerds http://www.mathnerds.com/mathnerds/ Math Goodies http://www.mathgoodies.com/ Your Teacher http://www.yourteacher.com/ AAA Math http://www.aaamath.com/ Algebra Help http://www.algebrahelp.com/ Math Power http://www.mathpower.com/ Discovery Education http://school.discoveryeducation.com/homeworkhelp/homework_help_h ome.html Yahoo Education http://education.yahoo.com/homework_help/math_help/ 93 Printable Worksheets Ed Helper http://edhelper.com/math.htm Purple Math http://www.purplemath.com/ Super Kids http://www.superkids.com/aweb/tools/math/ Drill Sheets http://donnayoung.org/math/drills.htm Math Slice http://www.mathslice.com/ Math Worksheets http://www.mathworksheets.org/ Math Drills http://www.math-drills.com/ Math Café http://www.mathfactcafe.com/ Free Worksheets http://www.freemathworksheets.net/ Aplus Math http://www.aplusmath.com/Worksheets/index.html The Math Worksheets Site http://themathworksheetsite.com/ Online Math Manipulatives National Library of Virtual Manipulatives http://nlvm.usu.edu/ Shodor http://www.shodor.org/interactivate/ NCTM http://illuminations.nctm.org/ActivitySearch.aspx 94 Online Math Games Ed Helper http://edhelper.com/math.htm Cool Math http://www.coolmath.com/ Fun Brain http://www.funbrain.com/ A+ Games http://www.aplusmath.com/games/ Cool Math 4 Kids http://www.coolmath4kids.com/ Math Playground http://www.mathplayground.com/games.html Gamequarium http://www.gamequarium.com/math.htm Primary Games http://www.primarygames.com/math.htm Math Games http://www.multiplication.com/interactive_games.htm Play Kids Games http://www.playkidsgames.com/mathGames.htm Video Console Math Games Brain Age Are you Smarter than a 5th Grader? 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Many times, this is because they have yet to form a firm understanding of math procedures. Other times, they do not understand the homework directions. While frustration is a natural response this, it's not the best way to work through difficulty. Effective Note Taking Writing notes for math class can be extremely helpful in middle school. This is because middle school math teachers cover a lot of material in each class period. Before the Lecture Students should have plenty of notebook paper ready. It is recommended that they draw a vertical line about 2 1/2' from the left margin all down the page, then label the left column 'recall' and the right one 'notes.' During the Lecture Students do not need to follow an outline form. It can be easier to write in simple paragraph form. Students shouldn't try to write down everything their teacher says; instead, they should try to capture all of the main ideas. With math class, students also need to write out examples of math problems. Examples used during class are often the same type of problems in the daily homework. After the Lecture Try to review notes immediately after school. Draw boxes around key words or phrases. Write all of the boxed words and phrases in the left hand recall section. This helps students remember the key subjects covered in each class period. Students can also put key formulas and equations in the left hand column. This will make finding pertinent information easier when trying to complete math homework.. Help from Friends and Family Sometimes middle school students fail to understand the sample problems provided in their class notes and textbook. When this happens, they should consult the advice of their friends or family. Students often forget that their older siblings or parents once studied similar topics and faced similar difficulties in their middle school math classes. 99 While a middle schooler should never expect others to complete their homework for them, they can ask questions on how to complete a problem. Another solution is to contact a classmate for help. The classmate might be able to further explain the instructions given in class. Additionally, middle school students can compare homework answers to see if they need to rework through a problem to get the correct answer. Additional Help If a student consistently has problems with math, they might also want to ask their middle school math teacher for additional help outside of school. The teacher should be able to provide help or recommend a tutor to help strengthen the student's math skills. 100 101 National Standards Link: http://standards.nctm.org/ Ohio State Standards Links: www.ode.state.oh.us Follow directions to Academic content standards ( Mathematics) http://www.ode.state.oh.us/GD/Templates/Pages/ODE/ODEDetail. aspx?page=3&TopicRelationID=1704&ContentID=801&Content=50719 Practice test and Released Materials are also available from this site. 102 Real Number Properties Review Properties of Addition Commutative Associative Algebraic Expression a+b=b+a (a + b) +c = a + (b + c) Identity Inverse Sign Rules + + + = + -- + -- = -- a+0=a a + -a = 0 Example 5 +3 = 8 (-6) + (-3) = -9 5 + (-5) = 0 + + -- or -- + + 9 + (-12) = -3 (-3) + 6 = 3 Subtraction Rule a – b = a + (-b) 7 – 3 = 7 + (-3) Properties of Multiplication Commutative Associative Algebraic Expression ab = ba (ab)c = a(bc) Identity Multiplicative Inverse Property Zero ax1=a 1 a 1 a ax0=0 Sign Rules + + = + -- -- = + + -- or -- + Example 3 4 = 12 (-3) (-5) = 15 (-3 ) 2 = -6 3 (-4) -12 Meaning The order numbers are added in does not matter. You may regroup the numbers to make arithmetic easier to do. Adding zero to a number does not change it. A number plus its opposite always equals zero. Meaning The sum of two positive numbers is positive. The sum of two negative numbers is negative. Subtract the absolute values. Then determine the sign: 1) The sum is zero if the numbers are opposites. 2) The sum is positive if the positive number has the greatest absolute value. 3) The sum is negative if the negative number has the greatest absolute value. For subtraction, keep the first number the same; transform the minus sign to a plus sign; and change the second number to its opposite. Use the addition rules to complete. Meaning The order numbers are multiplied in does not matter. You may regroup the numbers to make arithmetic easier to do. Multiplying a number by 1 does not change it. Multiplying a number by its reciprocal always equals 1. Multiplying a number by zero always gives a product of zero. Meaning If the signs are the same the product is positive. If the signs are the same the product is positive. If the signs are different the product is negative. ***The sign rules for division are the same as those for multiplication. Properties of Addition and Multiplication Distributive Algebraic Expression a(b+c) = ab + ac Meaning The numbers inside the parentheses must both be multiplied by the number outside the parentheses. 5(2 + 7) = (5 2) + (5 7) 103 Multiplication Chart 104