Integrated Math 1 / Unit 1: Quantities and Expressions
1.3 Order of Operations
Notes
Follow PEMDAS: Parentheses, Exponents, Multiplication and Division (left to right), then Addition and Subtraction (left to right).
- Grouping symbols include parentheses, brackets and fraction bars.
- Multiplication and division have equal rank, so work left to right. Same for addition and subtraction.
- To evaluate an expression, substitute the value of the variable (use parentheses) and then follow the order.
- Example: $2x^2 - 3x$ for $x = 5$: $2(25) - 15 = 35$.
Practice
Evaluate $6 + 4 \cdot 3^2$.
Exponent first: $3^2 = 9$. Then $4 \cdot 9 = 36$, and $6 + 36 = 42$.
Evaluate $2x^2 - 3x$ when $x = -4$.
$2(16) - 3(-4) = 32 + 12 = 44$. Square $-4$ first, not $2x$.
Simplify $(18 - 6) \div 3 \cdot 2$.
$12 \div 3 = 4$, then $4 \cdot 2 = 8$. Work left to right.
Ready for more? Take the Unit 1 test.