Year 7 · Four operations
Add and subtract whole numbers
Definition
When a calculation mixes operations, BIDMAS tells you the order: Brackets, Indices, Division and Multiplication, then Addition and Subtraction. It makes sure everyone gets the same answer.
Why Do I Have to Learn This?
The order of operations is the rule that stops one sum having two different answers. It keeps everyone’s working, and every calculator, in agreement.
Key Rules:
- 1. Do everything inside brackets first.
- 2. Division and multiplication rank equally, work left to right.
- 3. Addition and subtraction come last, also left to right.
Remember:
- •(5 + 3) × 2 is not 5 + 3 × 2, the brackets change the answer.
- •BIDMAS does not mean "all multiplication before all division", they share a step.
- •A fraction bar acts like a bracket around the top and the bottom.
BIDMAS
The order for working things out: Brackets, Indices, Division and Multiplication, Addition and Subtraction.
In 2 + 3 × 4 you multiply first, so the answer is 14, not 20.
Animated Example:
Free Add and subtract whole numbers Worksheet
Download free worksheets and practise today.
Every download has a fresh set of questions.
Let’s Practise the Concept
Step 1 of 3
Jump along the line
Start at 69 and jump on 21. Tap where you land.
Tap the line where 69 + 21 belongs.