| signed numbers | positive numbers, negative numbers and zero |
| opposite of a number | the number that is the same distance from zero on the number line but in the opposite direction, the opposite of -3 is 3. -(-3) means the opposite of negative three |
| absolute value | the distance of a number from zero on the number line, never negative |
| additive inverse | the opposite of a number, the sum of a number and its additive inverse is 0 |
| variable | letters that represent numbers |
| algebraic expression | any combination of letters, numbers, operations and grouping symbols |
| equation | a sentence of algebraic expressions with an equals sign |
| solution | a number that can be substituted for a variable that makes an equation true |
| distributive property | if a, b and c are numbers the distributive property says a(b+c) = ab + ac |
| like terms | terms with exactly the same variable to the same exponents |