What is BODMAS?

BODMAS is a memory aid for the order in which to do a calculation: Brackets first, then Orders (powers and roots), then Division and Multiplication together from left to right, then Addition and Subtraction together from left to right. It is the same rule as BIDMAS, BEDMAS and the American PEMDAS; only the words differ. The most common mistake is treating division as always before multiplication, or addition as always before subtraction, when the pairs have equal rank and are simply worked left to right.

Examples

• 4 + 3 × 5 = 4 + 15 = 19, because multiplication comes before addition.
• (4 + 3) × 5 = 7 × 5 = 35, because brackets come first.
• 12 ÷ 3 × 2 = 4 × 2 = 8, working left to right, not 12 ÷ 6 = 2.

Quick facts

• BODMAS and BIDMAS are used in the UK and Australia; PEMDAS is used in the United States; BEDMAS in Canada.
• Division and multiplication have equal rank, and so do addition and subtraction: work them left to right.
• A scientific calculator follows BODMAS automatically; a basic four-function calculator does not.