# Closure

## Formulas

Closure Property of Addition Sum (or difference) of 2 real numbers equals a real number Additive Identity a + 0 = a Additive Inverse a + (-a) = 0 Associative of Addition (a + b) + c = a + (b + c) Commutative of Addition a + b = b + a Definition of Subtraction a - b = a + (-b) Closure Property of Multiplication Product (or quotient if denominator 0) of 2 reals equals a real number Multiplicative Identity a * 1 = a Multiplicative Inverse a * (1/a) = 1 ? ? (a 0) (Multiplication times 0) a * 0 = 0 Associative of Multiplication (a * b) * c = a * (b * c) Commutative of Multiplication a * b = b * a Distributive Law a(b + c) = ab + ac Definition of Division a / b = a(1/b)

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