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FRACTIONS AND DECIMALS TYPES OF FRACTIONS A fraction is a part of a whole. There are many types of fractions. Simple Fraction - a fraction in which the numerator and denominator are both integers. Also known as a common fraction. Examples: 2 7 6 5 3, 3 ,7, 1 Proper Fraction - a fraction in which the numerator is less than the denominator. Examples: 1 2 1 4, 7, 8 Improper Fraction - a fraction in which the numerator is equal to or greater than the denominator. Improper fractions are usually changed to whole or mixed numbers. Examples: 5 7 11 3 , 7, 8 Mixed Number - a number that is a combination of an integer and a proper fraction. Thus, it is "mixed." 2 7 1 2 3, 5 8 , 2 2 Examples: Unit Fraction -a fraction in which the numerator is one. Examples: 1 1 5 ,1 An Integer Represented as a Fraction -a fraction in which the denominator is one. Examples: 2 3 1 , 1 Complex Fraction - a fraction in which the numerator or the denominator, or both numerator and denominator, are fractions. Examples: 3 5 7 8 7 9 4 , , 5 1 3 , Reciprocal- the fraction that results from dividing one by that number. Example: 4 is the reciprocal of 1 1 4 1 Zero Fraction - a fraction in which the numerator is zero. A zero fraction equals zero. 0 Example: "3 = 0 Undefined Fraction - a fraction with a denominator of zero. (7/0 means 7 divided by 0, which is impossibility because nothing can be divided by 0. Therefore, the fraction remains undefined.) Indeterminate Form - an expression having no quantitative meaning. 0 Example: 0 EQUIVALENT AND BASIC FRACTIONS Fractions are used to express parts of a whole in regards to lengths, volumes, weights, and other measures. We can say that we have: 1/2 of a glass of water, 7/8 of a pizza or, 3/10 of the provinces in Canada are Prairie Provinces. When two or more fractions have the same value, they are called equivalent fractions and the chart below shows this. We can see from the chart above that: 1/2 = 2/4 = 3/6= 4/8 = 6/12 or 1/3 = 2/6 = 4/12 etc. 2 To make equivalent fractions we must multiply or divide the numerator and denominator by the same number EXAMPLE # 1 3 5 3x2 5x2 = EXAMPLE # 2 6 10 = 8 12 = 8/4 12 / 4 = 2 3 A basic fraction is formed when we can no longer divide both the numerator and denominator by any number other than the number 1. EXAMPLE # 1 36 42 = 36 / 2 42 / 2 = 18 / 3 21 / 3 = 6 7 EXAMPLE # 2 64 / 8 8/2 = 80 / 8 = 10 / 2 64 80 4 = 5 ADDITION AND SUBTRACTION OF FRACTIONS Rules For Adding and/or Subtracting Fractions 1. Convert all mixed fractions to improper fractions. 2. Find a common denominator. 3. Keeping the denominator the same, either add or subtract the numerators. 4. Convert your answers to mixed fractions if necessary and reduce your fraction. 2/3 10 / 15 + + Example # 1 4/5 12 / 15 = = = ? 22 / 15 1 7 / 15 51/4 21 / 4 63 /12 - Example # 2 3 5/6 = ? 23 / 6 = ? 46 / 12 = 17 / 12 = 1 5 / 12 MULTIPLICATION AND DIVISION OF FRACTIONS Rules For Multiplying Fractions 1. Convert all mixed fractions into improper fractions. 2. Reduce the fractions if possible by finding the GCF. 3. Multiply the numerators (top parts) together. 4. Multiply the denominators (bottom parts) together. 5. Convert your fractions to mixed fractions and reduce if necessary. EXAMPLE # 1 3/4 X 14/15 = ? 1/2 X 7/5 = 7/10 EXAMPLE # 2 2 1/ 2 X 3 3/ 4 = ? 5/2 X 15/4 = 7 5/8 = 9 3/8 Rules For Dividing Fractions 1. Convert all mixed fractions to improper fractions. 2. Write the reciprocal or multiplicative inverse of the divisor. (Flip the second fraction.) 3 3. Proceed as you would in a multiplication question. EXAMPLE # 1 4/9 / 10/12 = ? 4/9 / 12/10 = 8/15 EXAMPLE # 2 3 1/3 / 2 2/5 = ? 10/3 / 12/5 = 10/3 X 5/12 = 25/18 = 1 7/18 DECIMAL NOTATION Numbers have different values depending on where they are placed in a string of numbers. In the case of decimals, the first number to the right of the decimal is in the tenths spot, the second number is in the hundredths spot, the third number is in the thousandths spot and so on. The number 27.6581 written below shows the value of each digit. 2 7 tens ones . . 6 tenths 5 8 1 hundredths thousandths ten-thousandths When we write 27.6581 in expanded form we would get either: (2 x 10) + (7 x 1) + (6 x 0.1) + (5 x 0.01) + (8 x 0.001) + (1 x 0.0001) or (2 x 10) + (7 x 1) + (6 X l/10) + (5 x l/100 + (8 x l/1000) + (1 x l/10 000) In word form 27.6581 would be: twenty-seven and six thousand five hundred eight-one ten thousandths. The number in standard form is 27.6581 PLACE VALUE CHART 4 TYPES OF DECIMALS In the broadest sense, a decimal is any numeral in the base ten number system. Following are several types of decimals. Decimal Fraction - a number that has no digits other than zeros to the left of the decimal point. Examples: 0. 349 , .84 , 0.3001 Mixed Decimal - an integer and a decimal fraction. Examples: 8.341 , 27.1 , 341.7 Similar Decimals - decimals that have the same number of places to the right of the decimal point. Examples: 3. 87 and .12 , 14.015 and 3. 396 Decimal Equivalent of a Proper Fraction proper fraction. Examples: .25 = 1 / 4 , - the decimal fraction that equals the .3 = 3 / 10 Finite (or Terminating) Decimal - a decimal that has a finite number of digits. Examples: . 3 , . 2765 , . 38412 Infinite (or Nonterminating) Decimal - a decimal that has an unending number of digits to the right of the decimal point. Examples: , √3, √33, √37, 34.12794 . . . Repeating (or Periodic) Decimal - Non terminating decimals in which the same digit or group of digits repeats. A bar is used to show that a digit or group of digits repeats. The repeating set is called the period or repent end. All rational numbers can be written as finite or repeating decimals. Examples: .3, .37 Nonrepeating (or Nonperiodic) Decimal- decimals that are non-terminating and non repeating. Such decimals are irrational numbers. Examples: 'IT, . √3 CONVERTING DECIMALS to FRACTIONS When converting decimals to fractions, the very last number to the right of the decimal tells us what our denominator will be when we write the fraction. The denominator will be one of the following: 10, 100, 1000, 10 000, 100 000, etc., depending upon the place value of the last number to the right of the decimal. The examples below show how this conversion is done. 5 EXAMPLE #1 EXAMPLE #2 Convert 0.36 to a fraction. Convert 4.537 to a fraction. Since the last number to the right of the decimal Since the last number to the right of the decimal is in is in the thousandths place, the denominator is the hundredths spot, the denominator is 100. 1000. :. 0. 36 = 36 Reduce if possible 100 = 36 100 9 Divide numerator & denominator by 4 25 :. 4.537 = 4 537/1000 =9 25 CONVERTING FRACTIONS to DECIMALS To convert a fraction into a decimal we divided the denominator (bottom part of the fraction) into the numerator (top part of the fraction). If the fraction is a mixed fraction, we must first convert it into an improper fraction before we divide. The examples below show how this is done. EXAMPLE #1 EXAMPLE #2 Convert 3 / 8 into a decimal. Convert 3 4 / 9 into a decimal. 0.375 8 ) 3.000 2 4xx 60 56x 40 40 0 :. 3/8 = 0.375 3 4/9 = 31/ 9 Mixed to Improper 3.444 ... 9)31.00 27 xx 40 36 40 36 4 :, 3 4/9 = 3. 6 COMPUTATION INVOLVING DECIMALS Adding and Subtracting Decimal Numbers Whenever a question requires you to add or subtract numbers with decimals, you must remember to line up your decimals before you find the sum or difference, as shown in the examples below. 6 Multiplying Decimal Numbers When multiplying numbers with decimals, it is not necessary to line up the decimals as we did when we were adding and subtracting. The examples below show how we multiply numbers with decimals. EXAMPLE # 1 Find the product of 4.54 and 2.5 4.54 x 2.5 2 270 9 080 11.350 (The factors have a total of 3 numbers to the right of the decimal point so we move the decimal 3 places to the left in the product.) EXAMPLE # 2 Multiplication using the powers of 10 2.54 x 10 = 25.4 2.54 x 100 = 254 2.54 x 1000 = 2540 2.54 x 10 000 = 25 400 (The decimal moves to the right the same number of places as there are zeros.) Dividing Decimal Numbers The example below shows the procedure and rules to follow when dividing numbers with decimals. EXAMPLE: # 1 EXAMPLE # 2 2.6 8.3.) 21.5.8 Division using the powers of 10 16 6 x 4 98 4 98 0 ( We must move the decimal to the right of the divisor and we must move the decimal the same number of places to the right in the dividend. The decimal is now placed directly above in the quotient.) EXAMPLE # 1 Find the sum of 82.635, 325.68 and 53.47 82.635 + 325.68 + 53.47 461.785 25.4 + 10 = 2.54 25.4 + 100 = 0.254 25.4 + 1000 = 0.0254 25.4 + 10 000 = 0.00254 (The decimal moves to the left the same number of places as there are zeros in the divisor.) EXAMPLE # 2 Find the difference between 7836.25 and 4532.78 7836. 25 3303. 47 - 4532. 78 7