Evaluating expressions

Math

Definition

Evaluating an expression means substituting given values for variables and then simplifying using the order of operations (PEMDAS/BODMAS) to find a numerical result.

How It Works

  1. Substitute the given value(s) for each variable
  2. Follow the order of operations: parentheses, exponents, multiplication/division, addition/subtraction
  3. Simplify to get the final answer

Examples

  • Evaluate 3x + 2 when x = 4: 3(4) + 2 = 14
  • Evaluate a² - 2b when a = 5 and b = 3: 25 - 6 = 19
  • Evaluate (n+1)(n-1) when n = 7: 8 × 6 = 48

Related Terms

Variables and expressions Order of operations Combining like terms Function notation

Study This Concept

Practice evaluating expressions with free review games in these units:

Pre-Algebra Unit 5: Variables and Expressions