Variables and expressions

Math

Definition

A variable is a letter or symbol that represents an unknown or changeable value. An expression is a mathematical phrase that combines numbers, variables, and operations (like +, −, ×, ÷) but does not contain an equals sign.

Examples

  • In the expression 3x + 5, x is the variable and 3 is the coefficient
  • The expression 2(n − 4) represents 'twice the difference of n and 4'
  • If a movie ticket costs d dollars, then 4d represents the cost of 4 tickets

Related Terms

Evaluating expressions Combining like terms Distributive property Order of operations

Study This Concept

Practice variables and expressions with free review games in these units:

Algebra 1 Unit 1: Foundations of Algebra