Evaluating Expressions

An expression is a combination of numbers, variables, and operators (such as +, -, *, /) that represents a value.

To evaluate an expression means to calculate its value by substituting the variables with their given values.

44

10

46

57

53

A variable is a symbol (usually a letter) that represents an unknown value in an expression.

The order of operations is a set of rules that determines the sequence in which calculations are performed: Parentheses, Exponents, Multiplication and Division (from left to right), Addition and Subtraction (from left to right). This is often remembered by the acronym PEMDAS.

An expression does not have an equality sign and represents a value, while an equation states that two expressions are equal.