BODMAS / BIDMAS Explained
Understand why the order you do calculations matters, what BODMAS (BIDMAS) means, common mistakes, and those viral maths problems that break the internet.
Ever seen one of those viral maths problems on social media where thousands of people get different answers? Like 8 ÷ 2(2+2) = ?. The reason people disagree is because they're not followingBODMAS (also called BIDMAS or PEMDAS).
What Is BODMAS?
BODMAS tells you the order to do operations in a calculation:
| Letter | Stands for | Example |
|---|---|---|
| B | Brackets | (3 + 2) = 5 |
| O / I | Orders / Indices (powers) | 2³ = 8 |
| D | Division | 12 ÷ 4 = 3 |
| M | Multiplication | 3 × 5 = 15 |
| A | Addition | 4 + 6 = 10 |
| S | Subtraction | 10 − 3 = 7 |
Important: Division and Multiplication are equal in priority — do them left to right. Same for Addition and Subtraction.
Why Does It Matter?
Consider: 3 + 4 × 2
- Wrong (left to right): 3 + 4 = 7, then 7 × 2 = 14 ✗
- Correct (BODMAS): 4 × 2 = 8 first, then 3 + 8 = 11 ✓
Worked Example 1
Calculate: 5 + 3² × 2
- Orders first: 3² = 9
- Multiply: 9 × 2 = 18
- Add: 5 + 18 = 23
Worked Example 2
Calculate: (8 + 2) × 3 − 4²
- Brackets: (8 + 2) = 10
- Orders: 4² = 16
- Multiply: 10 × 3 = 30
- Subtract: 30 − 16 = 14
Worked Example 3
Calculate: 20 ÷ 4 + 3 × 2 − 1
- Division: 20 ÷ 4 = 5
- Multiply: 3 × 2 = 6
- Left to right: 5 + 6 − 1 = 10
Common Mistakes
- Doing addition before multiplication. Remember: × and ÷ come before + and −.
- Forgetting that division and multiplication are equal. Do them left to right, not division first.
- Not working out brackets first. Always start inside the brackets.
The Viral Problems Explained
8 ÷ 2(2+2) = ?
- Brackets: (2+2) = 4
- Now we have: 8 ÷ 2 × 4
- Left to right: 8 ÷ 2 = 4, then 4 × 4 = 16
Some people get 1 because they multiply 2×4 first, but BODMAS says go left to right when ÷ and × are at the same level.
6 ÷ 2(1+2) = ?
- Brackets: (1+2) = 3
- Now: 6 ÷ 2 × 3
- Left to right: 6 ÷ 2 = 3, then 3 × 3 = 9
Try It Yourself
- 4 + 6 × 3 = ? (Answer: 22, not 30)
- (5 + 3) × 2² = ? (Answer: 32)
- 12 ÷ 3 + 2 × 5 − 1 = ? (Answer: 13)
- 2 + 3 × 4 − 6 ÷ 2 = ? (Answer: 11)
- (10 − 2²) × 3 + 1 = ? (Answer: 19)