Order of Operations

In a Nutshell

BIDMAS tells you which part of a calculation to tackle first so everyone gets the same answer.

When a calculation has more than one operation, the order matters. Without a convention, $3 + 4 \times 2$ could be 14 or 11. BIDMAS settles the argument.

Brackets first, then Indices (powers and roots), then Division and Multiplication (left to right), then Addition and Subtraction (left to right).

Division and multiplication have equal priority. So do addition and subtraction. When two operations share a priority level, work from left to right.

Try:

Press "Next step" to walk through the calculation one operation at a time. The colour shows which BIDMAS rule is being applied.

Watch it work

Question: Evaluate $(5 + 3) \times 2^2 - 4$ .

Have a go

Q1. Evaluate $6 + 2 \times 5$ .

Q2. Evaluate $(8 - 3)^2 + 1$ .

Q3. Evaluate $12 \div 4 + 3 \times 2$ .

Q4. Insert one pair of brackets to make this true: $4 + 2 \times 3 = 18$ .