Download Grade 6 Math

Grade 6 Math
Number Concepts, Number Operations Review
Important Words to Know
Addition
Sum
Total
All together
Subtraction
Difference
More than
Take away
Multiplication
Division
Product
Quotient
of
half (divide by 2)
times
Double (times by 2)
Whole Number Rounding
1. Underline the number you need to round (use place value chart)
2. Look at the number directly to the right of your underlined number.
3. If it is: 5 or greater, change your underline number one up, change all other
numbers behind it to a 0.
If it is: 4 or less, keep your number the same, change all other numbers behind it
to a 0.
Example:
4 564 - round to the nearest hundred
The number to the right of the 5 is a 6.
The 6 tells the 5 to round up.
Change the 5 to a 6.
All numbers behind the changed 6, changes to 0.
4 564 - 4 600
Decimal Rounding
1. Underline the number you need to round (use place value chart)
2. Look at the number directly to the right of your underlined number.
3. If it is: 5 or greater, change your underline number one up, drop all other numbers
behind it.
If it is: 4 or less, keep your number the same, drop all other numbers behind it.
Example:
4.464 - round to the nearest tenth
The number to the right of the 4 is a 6.
The 6 tells the 4 to round up.
Change the 4 to a 5.
All numbers behind the changed 5 are dropped.
4.464 - 4.5
Conversions (Percents, Decimals, Fractions)
Percents to Decimals
 Move the decimal 2 places to the LEFT! (or in your calculator, divide by 100)
Example:
75% = 0.75 or (75 divided by 100 = 0.75)
Decimals to Percents
 Move the decimal 2 places to the RGIHT! (or in your calculator, multiply by 100)
Example:
0.784 = 78.4% or ( 0.784 x 100 = 78.4%)
Fractions to Percents
 Top number (numerator) divided by the bottom number (denominator) multiply by
100.
Example:
½ = 1 divided by 2 x 100 = 50%
Fractions to Decimals
 Top number (numerator) divided by the bottom number (denominator)
Example:
½ = 1 divided by 2 = 0.50
Decimals to Fractions
 Change the decimal to a percent (see above)
 Put number over 100
 Reduce the fraction if possible (see below on how to reduce)
Example:
0.78 = 78% or ( 0.78 x 100 = 78%)
78
100
=
39
50
Percent of a Number
1. Change the percent to a decimal
2. Multiply
Example:
25% of 45 = 0.25 X 45
= 11.3
***Remember if it is a sale, you must SUBTRACT it from the original price.
Example:
You get 25% off of a sweater that costs $45.00. How much do you pay for the
sweater?
25% of 45 = 0.25 X 45
= 11.3
$45.00 - $11.30 = $33.80
Converting Fractions (Improper to Proper )
***Using your calculator:
Improper to Proper Fractions
 Type improper fraction into your calculator
 Hit the equals sign (=)
Example:
35
3
Type: 35
abc
11 2
=
3
3
Proper Faction to Improper Fractions
 Type proper fraction into your calculator
 Hit 2nd function button (yellow button)
 Hit abc button
Example:
11
2
3
abc
Type: 11
2
abc
3
2nd
abc
35
3
Equivalent Fractions
 Choose a number, and multiply or divide both the top number (numerator) and the
bottom number (denominator) by this number
Example:
1
3
x 4
x 4
=
4
12
Reducing Fractions
***Using your calculator:


Type fraction into your calculator
Hit the equals sign (=)
Example:
15
30
Type: 15
abc
30
= 1
1
2
Greatest Common Factor
 Factors are the numbers you multiply together to get a product.
 All numbers have at least 2 factors: 1 and itself
Example:
12 = 1 x 12, 2 x 6, 3 x 4
So the factors are:
12 = 1, 2, 3, 4, 6, 12
The GCF or Greatest Common Factor is the largest factor that is common to a set of
number.
Example:
12 = 1, 2, 3, 4, 6, 12
6 = 1, 2, 3, 6
The GCF of these numbers is 6.
Lowest Common Multiple
 Multiples are numbers that can be divided into your number (count by your number!)
 Multiples = many, they go on forever!
Example:
3 = 3, 6, 9 ,12, 15, etc…
The Lowest Common Multiple or LCM of a set of numbers is the smallest multiple they
have that are the same.
Example:
3 = 3, 6, 9, 12, 15, etc.
The LCM = 12
4 = 4, 8, 12, 16, etc.
Prime Numbers
 Have only 2 factors – one and itself! There are no other ways to make it by
multiplying.
Examples:
2=1x2
3=1x3
17 = 1 x 17
Composite numbers
 Have more that 2 factors (There is more that only one way to make it by multiplying)
Examples:
6 = 1 x 6 and 2 x 3
9 = 1 x 9 and 3 x 3
12 = 1 x 12, 2 x 6 and 3 x 4
Prime Factorization
 Are the prime numbers you multiply together to get a number, use a factor tree!
Example:
12
12 = 2 x 2 x 3 (Look at the last row of numbers)
2
2
6
2
3
Time
 There are 365 days in one year.
 There are 24 hours in one day.
 There are 60 minutes in every hour.
 There are 60 seconds in every minute.
Integers
 These are numbers that are both positive and negative (think temperature!)
Numberline: (Remember each end can go on forever!)
Etc….
-10, -9, -8, -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10
Smaller Numbers
Etc…
Larger Numbers