| A | B |
| number sentence | a mathematical sentence which shows a relationship between two expressions |
| equation | a number sentence that states two expression are equal |
| inequality | an example of a number sentence that is not an equation |
| variable | a letter or symbol that stands for a number |
| variable expression | an expression that contains at least one variable |
| replacement set | the set of all intended values for an open sentence |
| coefficient | the number in front of a variable - means to multiply |
| terms | each part of an expression separated by a + sign |
| open sentence | a number sentence that has a variable(s) |
| evaluate | to plug in a value for the variable |
| simplify | to restate an expression with its simplest name |
| value of the variable | the number they give you to use in place of the variable |