Simplification and approximation questions for bank exams are the fastest marks you can earn in prelims — if you know the shortcuts. Use BODMAS discipline, memorise squares up to 40 and cubes up to 20, convert fractions to percentages instantly, and round consistently toward the answer options. Target 20–30 seconds per question. This topic typically carries 10–15 of the 35 Quant questions in IBPS, SBI, and RBI assistant prelims, so a strong sprint here can seal your sectional cutoff.
- Why Simplification & Approximation Is the Highest-Weight Quant Topic
- Rules of the Sprint: Format, Timer, and Scoring
- Drill Set A: Simplification Questions (1–8)
- Shortcut Walkthrough A: BODMAS and Fraction Pairing Tricks
- Drill Set B: Approximation Questions (9–15)
- Shortcut Walkthrough B: Rounding, Squares up to 40, and Cube Tricks
- Answer Key with Full Solutions
- Score Analysis: Where You Stand
- Common Mistakes in Simplification and Approximation
- Memory Tools: Tables, Squares, Cubes, and Fraction-Percent Chart
- Next Steps: Practice Plan and Related Quant Topics
- Frequently Asked Questions
- Q: How many simplification questions come in IBPS PO prelims?
- Q: What is the difference between simplification and approximation?
- Q: Which squares and cubes should I memorise for bank exams?
- Q: Can I use the answer options to solve faster?
- Q: How do I avoid mistakes in approximation questions?
- Related reading
Why Simplification & Approximation Is the Highest-Weight Quant Topic
Across recent prelims patterns — IBPS PO/Clerk, SBI PO/Clerk, and RBI Assistant — the Quantitative Aptitude section has 35 questions in 20 minutes. Of these, simplification and approximation together typically account for 10–15 questions. No other single topic (percentage, ratio, or data interpretation) matches that density.
Why does this matter? Because these questions are formula-free. There is no caselet to decode, no DI set to interpret — just pure calculation speed. A candidate who solves 12 of these in under six minutes buys extra time for tricky arithmetic and DI questions later. That is why every toppers’ strategy starts with a daily simplification sprint.
Rules of the Sprint: Format, Timer, and Scoring
- Questions: 15 (Set A: 8 simplification, Set B: 7 approximation)
- Timer: 8 minutes total — that is roughly 32 seconds per question, mimicking real exam pressure.
- Negative-marking mindset: Bank prelims deduct 0.25 marks per wrong answer. If a question crosses 40 seconds, mark your best guess from unit-digit logic and move on.
- No calculator, no pen for rough work on the first pass — attempt mentally, and only write for squares/cubes you haven’t memorised yet.
Drill Set A: Simplification Questions (1–8)
Solve these exactly. Answers with full working are in the Answer Key below — don’t peek.
- Q1. 45 × 12 + 220 ÷ 4 − 85 = ?
- Q2. 7/8 of 640 + 3/5 of 450 = ?
- Q3. √1296 + √625 − 18 = ?
- Q4. (15% of 480) + (25% of 240) = ?
- Q5. 23 × 27 − 19 × 21 = ?
- Q6. 3 3/4 + 5 5/6 − 2 1/2 = ? (mixed fractions)
- Q7. 144 ÷ 16 × 8 + 36 = ?
- Q8. If 5x − 40 = 3x + 12, find x.
Shortcut Walkthrough A: BODMAS and Fraction Pairing Tricks
Before checking answers, absorb these three tricks — they solve 80% of Set A mentally:
- BODMAS with “of” = brackets-tier: “of” (i.e., multiplication by a fraction) is resolved right after brackets, before division. So 7/8 of 640 ÷ 2 means compute 7/8 × 640 first.
- Fraction pairing and cancellation: Convert percentages to fractions (25% = 1/4, 12.5% = 1/8) so that numbers cancel. 3/5 of 450 = 3 × 90 = 270 — no long multiplication needed.
- Unit-digit check: For Q5, the unit digit of 23 × 27 ends in 1 (3×7=21) and 19 × 21 ends in 9 — the difference must end in 2. This one check eliminates most wrong options instantly.
Drill Set B: Approximation Questions (9–15)
These carry the word “approximately” — round smartly and pick the nearest option.
- Q9. 39.97% of 449.8 + 24.89% of 240.1 ≈ ?
- Q10. √1520.5 + 23.92 × 4.98 ≈ ?
- Q11. (17.03)² + (11.98)² − (8.02)² ≈ ?
- Q12. 1249.87 ÷ 24.92 + 34.9% of 599.8 ≈ ?
- Q13. 63.98% of 749.9 − 15.02% of 1199.8 ≈ ?
- Q14. 3 √4911.6 ≈ ?
- Q15. (14.98)³ ÷ 224.7 ≈ ?
Shortcut Walkthrough B: Rounding, Squares up to 40, and Cube Tricks
- Round to whole numbers immediately: 39.97% of 449.8 is just 40% of 450 = 180. If a decimal ends in .97 or .02, the examiner designed it to be rounded.
- Squares up to 40 and cubes up to 20: Q11 becomes 17² + 12² − 8² = 289 + 144 − 64 = 369 only if 17² = 289 is instant recall. Drill these daily.
- Nearest perfect square/cube: √1520.5 ≈ √1521 = 39, and 3√4911.6 ≈ 3√4913 = 17, because 17³ = 4913. This is why cube recall up to 20 pays.
- Rounding direction in division: Round numerator and denominator in opposite directions (one up, one down) only when options are wide apart; round in the same direction when options are close, so errors cancel.
Answer Key with Full Solutions
| Q | Solution | Answer |
|---|---|---|
| 1 | 45×12=540; 220÷4=55; 540+55−85 | 510 |
| 2 | 7/8×640=560; 3/5×450=270; 560+270 | 830 |
| 3 | √1296=36; √625=25; 36+25−18 | 43 |
| 4 | 15% of 480=72; 25% of 240=60; 72+60 | 132 |
| 5 | 621−399 | 222 |
| 6 | 3 3/4 + 5 5/6 − 2 1/2 = (45+70−30)/12 = 85/12 | 7 1/12 |
| 7 | 144÷16=9; 9×8=72; 72+36 | 108 |
| 8 | 5x−3x=12+40; 2x=52 | 26 |
| 9 | ≈40% of 450 + 25% of 240 = 180+60 | ≈240 |
| 10 | √1521=39; 24×5=120; 39+120 | ≈159 |
| 11 | 17²+12²−8² = 289+144−64 | ≈369 |
| 12 | 1250÷25=50; 35% of 600=210; 50+210 | ≈260 |
| 13 | 64% of 750=480; 15% of 1200=180; 480−180 | ≈300 |
| 14 | 3√4913=17 | ≈17 |
| 15 | 15³=3375; 3375÷225 | ≈15 |
Score Analysis: Where You Stand
- 12–15 correct within 8 minutes: Prelims-ready on this topic. Shift to harder DI sets.
- 9–11 correct: Concepts are fine, recall is slow — your bottleneck is tables/squares memory, not method.
- Below 9: Rebuild BODMAS order and fraction-percent conversion before attempting more speed drills. Accuracy first, speed second.
Common Mistakes in Simplification and Approximation
- Sign errors: Subtracting a negative term incorrectly, or losing a minus sign mid-chain — the number one killer in Q5-style questions.
- Wrong rounding direction: Rounding both parts of a division the same way when options are close, doubling the error instead of cancelling it.
- Over-rounding: Rounding 24.89 to 25 is fine; rounding 1249.87 to 1000 is not. Round to the nearest convenient value, not the nearest “pretty” number.
- Misreading “approximately”: Doing exact arithmetic on approximation questions wastes 20+ seconds per question.
- Skipping BODMAS for left-to-right: In Q7, doing 144 ÷ (16 × 8) instead of (144 ÷ 16) × 8 gives a wrong answer in seconds.
Memory Tools: Tables, Squares, Cubes, and Fraction-Percent Chart
Memorise this fraction-percent chart cold — it converts half of all simplification work into mental arithmetic:
| Fraction | Percent | Fraction | Percent |
|---|---|---|---|
| 1/2 | 50% | 1/7 | 14.28% |
| 1/3 | 33.33% | 1/8 | 12.5% |
| 1/4 | 25% | 1/9 | 11.11% |
| 1/5 | 20% | 1/11 | 9.09% |
| 1/6 | 16.66% | 1/12 | 8.33% |
Beyond this: multiplication tables up to 20, squares up to 40, cubes up to 20. Ten minutes of daily flash-card recall for two weeks will cut your average solving time nearly in half.
Next Steps: Practice Plan and Related Quant Topics
- Daily: One 15-question sprint (8 minutes) — track accuracy and time in a log.
- Weekly: One full 35-question Quant sectional mock, timed at 20 minutes.
- Build next: Move from simplification into percentages (it feeds approximation directly), ratio and proportion, and then data interpretation — where these calculation skills compound into 10–15 more marks.
Check official notifications and exam patterns on ibps.in, sbi.co.in, and rbi.org.in before finalising your prep plan, since weightage can shift year to year.
Frequently Asked Questions
Q: How many simplification questions come in IBPS PO prelims?
Typically 10–15 questions out of 35 in the Quant section, based on recent exam patterns — split between exact simplification and approximation. The exact mix varies by slot and year.
Q: What is the difference between simplification and approximation?
Simplification gives an exact answer using BODMAS; approximation uses rounding to arrive at the nearest value and is signalled by words like “approximately” or “≈” in the question.
Q: Which squares and cubes should I memorise for bank exams?
Squares up to 40 and cubes up to 20, plus fraction-percent conversions like 1/8 = 12.5% and 1/6 = 16.66%. These three memory blocks cover the vast majority of drill questions.
Q: Can I use the answer options to solve faster?
Yes — option elimination via unit digits and digit sums is a verified shortcut in the MCQ format. If only one option has the right unit digit or digit-sum behaviour, you can mark it without completing the full calculation.
Q: How do I avoid mistakes in approximation questions?
Round consistently in line with the gap between options, and always recheck the direction of rounding for division and square/cube roots — rounding both parts of a division the same way compounds error instead of cancelling it.
Related reading
- Simple vs Compound Interest Shortcuts: Ratio Trick and Difference Formula for SSC & Bank Exams
- Wednesday Warm-Up Quiz: 15 Puzzles and Seating Arrangement Questions for Banking Mains
Quick revision
- Questions: 15 (Set A: 8 simplification, Set B: 7 approximation)
- Timer: 8 minutes total — that is roughly 32 seconds per question, mimicking real exam pressure.
- Negative-marking mindset: Bank prelims deduct 0.25 marks per wrong answer. If a question crosses 40 seconds, mark your best guess from unit-digit logic and move on.
- No calculator, no pen for rough work on the first pass: — attempt mentally, and only write for squares/cubes you haven’t memorised yet.
- Q1.: 45 × 12 + 220 ÷ 4 − 85 = ?
- Q2.: 7/8 of 640 + 3/5 of 450 = ?
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