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Area of a triangle

1/2 base x height

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Area of a circle

Pi x radius squared

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Circumference of a circle

pi x diameter

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Pythagorean theorem

a^2 + b^2 = c^2 (c is hypotenuse)

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whole number

a nonnegative number that is not expressed as a fraction or a decimal

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Integer

a whole number or its opposite (number line)

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Composite number

a number that has more than two factors

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Order of operations

Parentheses, Exponents, Multiply/Divide, Add/Subtract (Please Excuse My Dear Aunt Sally)

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Commutative Property

5 x 2 = 2 x 5

(5) (a) = (a) (5)

b + 3 = 3 + b

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Associative Property

If parentheses can be moved to group different numbers in an arithmetic problem without changing the result, then the operation is associative. Addition and multiplication are associative.

2 + (3 + 4) = (2 + 3) + 4

2 (ab) = (2a) b

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Distributive Property

5a + 5b = 5(a + b)

5(100 - 6) = (5 x 100) - (5 x 6)

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Additive identity

The value that, when added to a number, does not change the number. For all integers, the additive identity is 0.

5 + 0 = 5

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Multiplicative identity

The value that, when multiplied by a number, does not change the number. For all integers, the multiplicative identity is 1.

5 x 1 = 5

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Multiplicative inverse

The number that, when multiplied by the number, gives you the multiplicative identity (1).

1/5 is the multiplicative identity of 5

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Additive inverse

The number that, when added to the number, give you the additive identity (0).

The additive inverse of 3 is -3

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Combination

Order does NOT matter

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Permutation

Order does matter

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