Understanding the BODMAS rule (Order of Operations) is essential for solving mathematical expressions correctly. However, in exams like CTET, questions are often designed to trap students using common mistakes rather than testing straightforward calculation.
This guide will help you identify common error patterns, understand why students go wrong, and learn how to avoid traps in CTET.
📌 What is BODMAS? (Quick Recap)
- B – Brackets
- O – Orders (powers, roots)
- D – Division
- M – Multiplication
- A – Addition
- S – Subtraction
👉 Division and Multiplication are done left to right, same for Addition and Subtraction.
🚫 Common BODMAS Errors with Examples
❌ Error 1: Solving Strictly Left to Right
Question: $8 + 4 \times 2$
Wrong: $8 + 4 = 12 \rightarrow 12 \times 2 = 24$
Correct: $4 \times 2 = 8 \rightarrow 8 + 8 = 16$
❌ Error 2: Multiplication Before Division Myth
Question: $24 \div 6 \times 2$
Wrong: $24 \div 12 = 2$
Correct: $24 \div 6 = 4 \rightarrow 4 \times 2 = 8$
❌ Error 3: Ignoring Brackets
Question: $10 - (2 + 3) \times 2$
Wrong: $10 - 2 + 3 \times 2 = 14$
Correct: $2 + 3 = 5 \rightarrow 5 \times 2 = 10 \rightarrow 10 - 10 = 0$
❌ Error 4: Ignoring Powers
Question: $3 + 2^3 \times 2$
Wrong: $3 + 2^6 = 67$
Correct: $2^3 = 8 \rightarrow 8 \times 2 = 16 \rightarrow 3 + 16 = 19$
❌ Error 5: Sign Confusion
Question: $10 - 4 \times 3$
Wrong: $(10 - 4) \times 3 = 18$
Correct: $4 \times 3 = 12 \rightarrow 10 - 12 = -2$
❌ Error 6: Multiple Brackets Confusion
Question: $20 - [4 + (3 \times 2)]$
Correct: $3 \times 2 = 6 \rightarrow 4 + 6 = 10 \rightarrow 20 - 10 = 10$
❌ Error 7: Over-Simplification
Question: $6 + 12 \div 3 \times 2$
Wrong: $6 + 12 \div 6 = 8$
Correct: $12 \div 3 = 4 \rightarrow 4 \times 2 = 8 \rightarrow 6 + 8 = 14$
🎯 CTET Exam Insight
CTET questions often focus on identifying mistakes rather than solving directly. You may be asked to analyze a student’s solution or choose the correct reasoning.
👨🏫 Teaching Perspective
- Encourage step-by-step solving
- Use arrows or visual aids
- Focus on reasoning, not shortcuts
- Ask students to explain each step
🔥 Smart Tips to Avoid Mistakes
- Always solve brackets first
- Look for powers before operations
- Follow left-to-right for ÷ and ×
- Double-check signs
🚀 Practice Challenge
$15 - 3 \times (2 + 4) + 6$
