BIDMAS — order of operations
Brackets, Indices, Division/Multiplication (left to right), Addition/Subtraction (left to right). Year 6 NC objective.
BIDMAS (Brackets, Indices, Division/Multiplication, Addition/Subtraction) is the order in which operations should be carried out. Without it, ‘3 + 4 × 2’ could be 14 or 11. The agreed answer is 11. Year 6 SATs expect children to apply BIDMAS reliably.
Worked examples
3 + 4 × 2 = 11. Multiplication first.
(3 + 4) × 2 = 14. Brackets override.
20 − 6 ÷ 2 = 17. Division first: 6÷2=3, then 20−3=17.
Frequently asked questions
Is it BIDMAS or BODMAS or PEMDAS?
BIDMAS, BODMAS (B is brackets, O is ‘Of’ or ‘Order’ = indices) and PEMDAS (US: Parentheses, Exponents, Multiplication, Division, Addition, Subtraction) are all the same rules with different acronyms.
Why × and ÷ tied?
They're inverses. Same priority, performed left to right. 12÷3×2 = 4×2 = 8 (NOT 12÷6=2).
Indices in KS2?
Year 6 introduces square (²) and cube (³) numbers. Strictly ‘indices’ in BIDMAS includes any power.