How to Solve Approximation Questions in Bank Exams
To solve approximation questions in bank exams, round every number to the nearest easy value (24.98% → 25%, 801.03 → 800, 14.99 → 15), follow BODMAS, and pick the option closest to your result. For example, 24.98% of 801.03 + 39.97% of 449.9 becomes 25% of 800 + 40% of 450 = 200 + 180 = 380 (the exact value is 379.92).
Key takeaway: Approximation is option elimination, not exact arithmetic. Round to numbers you can work with in your head (perfect squares, cubes, "friendly" percentages), keep the order of operations, and stop as soon as only one option is close. Aim for 20 to 30 seconds per question.
IBPS Clerk, SBI Clerk and RRB prelims often give five approximation or simplification questions, and PO prelims mix them into quantity comparisons. Each question below was worked exactly in Python to make sure the rounded answer really is the closest option.
Approximation Rules for Bank Exams (Rounding Rules)
| Rule | Example |
|---|---|
| Round decimals to the nearest whole number | 39.97 → 40, 8.02 → 8 |
| Round percentages to a friendly value | 24.98% → 25%, 33.31% → 33⅓% |
| Round inside roots to the nearest perfect square or cube | √624.8 → √625 = 25, ∛2196.9 → ∛2197 = 13 |
| Round a divisor so the division becomes exact | 1199.6 ÷ 39.98 → 1200 ÷ 40 = 30 |
| Keep BODMAS: brackets, of, division, multiplication, addition, subtraction | Do "of" and ÷ before + |
| Round large multiplications carefully | 1244.9 × 2.98: an error of 0.02 on 1245 is about 25 |
The last rule matters. Rounding 2.98 to 3 is safe when the other number is small, but on a four-digit number it moves the answer by around 25, which can matter if options are close.
Percentage to Fraction Table for Approximation
| Percentage | Fraction | Percentage | Fraction |
|---|---|---|---|
| 50% | 1/2 | 12.5% | 1/8 |
| 33⅓% | 1/3 | 11.11% | 1/9 |
| 25% | 1/4 | 10% | 1/10 |
| 20% | 1/5 | 9.09% | 1/11 |
| 16⅔% | 1/6 | 8.33% | 1/12 |
| 14.28% | 1/7 | 6.25% | 1/16 |
Learn squares up to 30 and cubes up to 20 too: 13² = 169, 17² = 289, 19² = 361, 21² = 441, 13³ = 2197, 14³ = 2744.
Approximation Questions with Solutions (IBPS and SBI Clerk Level)
What approximate value will come in place of the question mark?
Q1. 24.98% of 801.03 + 39.97% of 449.9 = ? 25% of 800 + 40% of 450 = 200 + 180 = 380 (exact 379.92).
Q2. (14.99)² − (8.02)³ ÷ 15.98 = ? 225 − 512 ÷ 16 = 225 − 32 = 193 (exact 192.42).
Q3. √624.8 × 11.97 + 1199.6 ÷ 39.98 = ? 25 × 12 + 30 = 330 (exact 329.21).
Q4. 3599.7 ÷ 8.99 × 1.99 + (17.02)² = ? 400 × 2 + 289 = 1089 (exact 1086.50).
Q5. ∛2196.9 + 64.97% of 199.8 = ? 13 + 130 = 143 (exact 142.81).
Q6. (?)² = 44.04% of 349.98 + 205.01% of 140.01 154 + 287 = 441, so ? = 21 (exact 21.004).
Q7. 124.98 × 3.02 + 3599 ÷ 8.98 + (17.99)² = ? 375 + 400 + 324 = 1099 (exact 1101.86).
Q8. ?% of 799.8 = 31.97 × 15.02 − 79.9 480 − 80 = 400, and 400 is 50% of 800, so ? = 50 (exact 50.05).
Q9. (9.979)³ − (23.99)² + (1.99)⁵ = ? Options: 410, 430, 456, 490, 520. 1000 − 576 + 32 = 456. The exact value is 449.40, and 456 is still the nearest option. This shows why you compare with options: cubing 9.979 as 10 adds about 6, which is fine when options are 20 to 30 apart.
Q10. 7.98 × 34.97 + 1567.8 ÷ 13.99 = ? 8 × 35 + 1568 ÷ 14 = 280 + 112 = 392 (exact 391.13).
Approximation Tricks to Save Time
- Scan the options first. If options are 100 apart, round boldly; if they are 5 apart, round only the small numbers.
- Convert percentages to fractions using the table above (Q1, Q5).
- Snap roots to perfect squares and cubes (Q3, Q5, Q6).
- Make divisions exact by adjusting the dividend slightly: 1567.8 ÷ 13.99 → 1568 ÷ 14 (Q10).
- Watch the direction of rounding. If you round two products up, the result runs high; balance one up and one down when options are close.
- For "?%" questions, compute the right side first and then express it as a share of the base (Q8).
- For "(?)²" questions, find the sum and look for the nearest perfect square (Q6).
These overlap heavily with simplification tricks for bank exams, and the digit work helps in missing number series too.
More Approximation Questions (PO Prelims Level)
Q11. ?% of 1249.8 = 18.02 × 24.97 − 50.1 18 × 25 − 50 = 400. 400 ÷ 1250 × 100 = 32 (exact 31.99).
Q12. √? = 23.98 × 2.01 + 1.97 24 × 2 + 2 = 50, so ? = 50² = 2500 (exact 2517; options are usually 100 or more apart here).
Q13. (?)³ = 3374.8 15³ = 3375, so ? = 15.
Q14. 45.05% of 1599.9 − 24.96% of 799.8 = ? 45% of 1600 = 720, 25% of 800 = 200, so 720 − 200 = 520 (exact 521.12).
Approximation with Fractions (Solved)
Fractions appear in newer papers. Make the whole number divisible by the denominator first.
Q15. 1/3 of 899.7 + 2/5 of 1250.2 = ? 900 ÷ 3 = 300 and 1250 × 2/5 = 500, so 800 (exact 799.98).
Q16. 7/9 of 3599.6 − 3/8 of 1599.8 = ? 3600 × 7/9 = 2800 and 1600 × 3/8 = 600, so 2200 (exact 2199.76).
How Approximation Differs Across Bank Exams
| Exam | What to expect | Rounding style |
|---|---|---|
| IBPS Clerk / SBI Clerk prelims | A set of about five simplification or approximation questions | Bold rounding; options far apart |
| IBPS PO / SBI PO prelims | Fewer direct questions, more inside quantity comparison | Careful rounding; options closer |
| RRB Clerk / RRB PO | Approximation sets are common | Same as clerk |
| Mains (all) | Rare as a set; used inside DI calculations | Round only at the last step |
Squares and Cubes Table for Approximation
| n | n² | n³ | n | n² | n³ |
|---|---|---|---|---|---|
| 11 | 121 | 1331 | 16 | 256 | 4096 |
| 12 | 144 | 1728 | 17 | 289 | 4913 |
| 13 | 169 | 2197 | 18 | 324 | 5832 |
| 14 | 196 | 2744 | 19 | 361 | 6859 |
| 15 | 225 | 3375 | 20 | 400 | 8000 |
Squares of 21 to 30: 441, 484, 529, 576, 625, 676, 729, 784, 841, 900.
How to Approach an Approximation Set in the Exam
- Read all five questions and start with the ones that have percentages and perfect squares; they are fastest.
- Spend at most 30 seconds on each. If the rounding is unclear after one pass, mark it and move on.
- Before marking an answer, check that no other option is within your rounding error.
- Come back to the marked questions only after the full quant section.
Simplification vs Approximation: What Is the Difference?
| Point | Simplification | Approximation |
|---|---|---|
| Numbers given | Exact, clean | Decimals near round values |
| Answer | Exact value | Nearest option |
| Typical stem | "What will come in place of ?" | "What approximate value will come in place of ?" |
| Method | BODMAS with exact arithmetic | Round, then BODMAS |
| Risk | Calculation slips | Over-rounding when options are close |
Common Mistakes in Approximation Questions
- Ignoring BODMAS after rounding (adding before dividing).
- Rounding 2.98 to 3 next to a four-digit number when options are close (see the rounding table).
- Converting a percentage to the wrong fraction (16.66% is 1/6, not 1/16).
- Not checking the options: approximation questions are designed so only one option is near.
Approximation Practice Questions (with Answers)
- 19.97% of 1500.2 + 12.02 × 14.99 = ? Answer: 480 (300 + 180; exact 479.77).
- √1295.7 × 7.02 − 49.99 = ? Answer: 202 (36 × 7 − 50; exact 202.70).
- 4199.8 ÷ 6.98 − 299.9 = ? Answer: 300 (600 − 300; exact 301.79).
- (21.03)² + (18.89)² = ? Answer: about 800 (441 + 357 = 798; exact 799.09, so pick the option nearest 800).
- 74.98% of 839.98 + 125.09% of 440.01 = ? Answer: 1180 (630 + 550; exact 1180.23).
- ∛2744.2 × 6.03 = ? Answer: 84 (14 × 6; exact 84.42).
- 16.02% of 449.9 + (11.99)² = ? Answer: 216 (72 + 144; exact 215.83).
- 999.8 ÷ 24.99 × 4.98 + 50.03 = ? Answer: 250 (40 × 5 + 50; exact 249.27).
- (?)² = 288.9 + 16.02 × 21.03. Answer: 25 (289 + 336 = 625; exact 25.02).
- 33.33% of 1199.7 + 66.67% of 600.2 = ? Answer: 800 (400 + 400; exact 800.01).
Practise under time in the IBPS Clerk Numerical Ability Sectional Mock Test 01 and the SBI Clerk Numerical Ability Sectional Mock Test 01.
Approximation Questions FAQs
How many approximation questions come in IBPS Clerk and SBI Clerk prelims?
Usually a set of about five simplification or approximation questions, so together they are among the most scoring topics in prelims.
How much should I round in approximation questions?
Round to the nearest whole number or friendly value, then compare with the options. Round less when options are close together.
Is BODMAS needed in approximation?
Yes. Rounding changes the numbers, not the order of operations.
Which squares and cubes should I learn?
Squares up to 30 and cubes up to 20 cover almost every approximation question in bank prelims.
Are approximation questions asked in SSC CGL?
Rarely in the bank format, but the same rounding habits speed up SSC simplification and data interpretation.
Practice Next
- Mock tests: IBPS PO Quantitative Aptitude Sectional Mock Test 01 and SBI PO Quantitative Aptitude Sectional Mock Test 03.
- Topic practice: IBPS Clerk Simplification & Approximation Mock Test 02 (every option checked so the exact value is nearest the key).
- New topic-wise test: IBPS Clerk Simplification and Approximation Mock Test 01: BODMAS, Percentage and Square Root Questions (20 Questions).
- Quick timed sets: IBPS Clerk Quant Mini Quiz 01 and SBI Clerk Quant Mini Quiz 01, or a full paper: SBI Clerk Prelims Full Mock Test 01.
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- Exam details: SBI Clerk 2026 notification.
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