This deep dive covers Common BIDMAS Mistakes within BIDMAS for GCSE Mathematics. Revise BIDMAS in Number for GCSE Mathematics with 14 exam-style questions and 22 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 3 of 9 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Common BIDMAS Mistakes
❌ Mistake 1: Working purely left to right
2 + 3 × 4 = 5 × 4 = 20 WRONG!
✅ Multiplication first: 2 + (3 × 4) = 2 + 12 = 14
❌ Mistake 2: Treating division and multiplication as separate priorities
12 ÷ 3 × 2 = 12 ÷ 6 = 2 WRONG!
✅ Left to right: (12 ÷ 3) × 2 = 4 × 2 = 8
❌ Mistake 3: Ignoring brackets with indices
2 × (3 + 1)² = 2 × 3 + 1² = 7 WRONG!
✅ Brackets first: 2 × (4)² = 2 × 16 = 32
Practice questions for BIDMAS
What does the letter 'I' stand for in BIDMAS?
Explain what BIDMAS tells us about calculations and why it is needed.
Quick recall flashcards
Calculate: 10 - 2²
**Step 1:** Indices first (BIDMAS)
2² = 4
**Step 2:** Then subtraction
10 - 4 = **6**
*(Not 10 - 2 = 8, then 8² = 64)*
Calculate: 2 + 3 × 4
**Step 1:** Multiplication first (BIDMAS)
3 × 4 = 12
**Step 2:** Then addition
2 + 12 = **14**
*(Not 2 + 3 = 5, then 5 × 4 = 20)*