STAAR Math REMEMBER THIS

Prime Number

A whole number greater than 1 that has exactly two factors (1 and itself) [ex:3] [ 3's only factors are 3 and 1]

Two-line strategy

Add the opposite (subtraction becomes addition, opposite sign (+ to - or - to +)

Opposite (inverse) of subtraction

Addition

[Inequalities} If you divide or multiply by a negative number, you must...

FLIP the inequality sign

≥

Greater than or equal to, closed circle, shade to the right

1.205 [ place value of 0]

Hundredths place

Dividing Fractions

KCF[ keep, change, flip]: *keep* your first fraction the same, *change* division to multiplication, *flip* the second fraction (reciprocal), then multiply like normal

≤

Less than or equal to, closed circle, shade to the left

Adding Decimals

Make sure to line up decimals

Subtracting decimals

Make sure to line up decimals

Percent to decimal

Move decimal two places to left. (25% to .25)

Decimal to percent

Move decimal two places to right. (.25 to 25%)

Opposite (inverse) of division

Multiplication

Multiplying fractions

Multiply the numerators Multiply the denominators Simplify the answer

Mixed Number to Improper Fractions

Multiply whole number by denominator, add that value to the numerator-that is your new numerator, your old denominator is your new denominator.

Adding fractions

Must have common denominator, then add the numerators

Fraction less than 1

Numerator less than the denominator

Decimal to fraction

Place fraction bar under decimal, decimal = 1, any number after = 0

Percent to fraction

Place percent over 100, reduce

Multiplying or dividing integers

Same sign positive, different sign negative *cue song*

Things you MUST ask for on the test

Scratch paper, highlighter, notecard

Adding integers with different signs

Subtract and keep the sign of the bigger number

Opposite (inverse) of addition

Subtraction

First thing to do when you get your test

Tear out reference sheet and mark it up

1.35 [ place value of 3]

Tenths place

On the left side of the number line, the farther from zero you are...

The smaller your numbers get

3.478 [ place value of 8]

Thousandths place

Fraction to decimal

Top dog gets the house, divide

Fraction to percent

Top dog gets the house, move decimal two places to the right

Subtracting two numbers

Use the two-line strategy

Adding integers with the same sign

add the numbers and keep the sign

Opposite (inverse) of multiplication

division

Mixed Number to Improper Fraction Example

e.g. 2 4/7 denominator= 7 numerator = denominator x whole number + original numerator 7 x 2 + 4 = 18 Answer: 18/7

Subtracting Fractions

find a common denominator then subtract the numerator

>

greater than

<

less than

fraction greater than 1

numerator is greater than the denominator

(1/4)^3 (3 is the exponent)

(1/4) x (1/4) x (1/4)

-5 compared to -2

-5 is SMALLER (less than) than -2

1/10

0.10

1/5

0.20

¼

0.25

1/3

0.33 repeating

2/5

0.40

½

0.50

3/5

0.60

2/3

0.66 repeating

¾

0.75

4/5

0.80

5/5

1

Dividing Decimals

1. If there is a decimal in the dividend, you draw an arrow up and that is where your arrow will be in the quotient 2. If there is a decimal in the divisor, you must move the decimal to the right until it is at the end of the number. 3. You must move the decimal back the same amount of times in the dividend.

How to set up a proportion

1. Line = Line 2. Label your lines 3. Plug in what you know (look for 3 things to plug in) 4. Solve for unknown (x)

Multiplying decimals

1. Multiple numbers as if whole numbers. 2. Then count total number of decimal places in the factors and add them (Ex: 2.2 and 2.33 has three total decimal places) 3. Add the total number of Decimal places to product, counting left to right (Ex: 22*233 = 5126 --> 5.126 final answer)

3 ways to solve a proportion

1. Up/down and down/up 2. Left/ right and right/left 3. Cross multiply (butterfly method)

Percent means per....

100

2^5 (5 is the exponent)

2 x 2 x 2 x 2 x 2