What Is the Order of Operations (PEMDAS)?
The order of operations is the set of rules that determines which calculations to perform first in a math expression.
Without these rules, 3 + 4 × 2 could be 14 (add first) or 11 (multiply first). The order of operations says: multiply first. The answer is 11.
The rules (PEMDAS)
- Parentheses — do what is inside parentheses first
- Exponents — calculate powers and roots
- Multiplication and Division — left to right (equal priority)
- Addition and Subtraction — left to right (equal priority)
Important: Multiplication and division have the same priority — work left to right. Same for addition and subtraction.
Example
Solve: 2 + 3 × (4 + 1)² ÷ 5
- Parentheses: (4 + 1) = 5 → 2 + 3 × 5² ÷ 5
- Exponents: 5² = 25 → 2 + 3 × 25 ÷ 5
- Multiplication/Division (left to right): 3 × 25 = 75, then 75 ÷ 5 = 15 → 2 + 15
- Addition: 2 + 15 = 17
Common mistakes
Doing addition before multiplication: 3 + 4 × 2 = 14 is wrong. Multiply first: 3 + 8 = 11.
Always doing multiplication before division: They are equal priority. 12 ÷ 3 × 2 = 8 (left to right), not 12 ÷ 6 = 2.
Thinking PEMDAS means M always comes before D: The M and D are worked left to right, as are A and S.
Related concepts
- How to Teach Order of Operations: full teaching guide
- Expressions: where order of operations is applied
- Exponents: the E in PEMDAS