A numerical ability plan for IBPS Clerk

In the prelims, Numerical Ability gives you 35 questions in 20 minutes. That is 1,200 seconds for 35 questions, or about 34 seconds a question. Nobody solves every question in 34 seconds. The candidates who do well answer the quick types in 15–25 seconds, bank the time, and spend it on one data interpretation set and a few arithmetic questions.

In the mains, Quantitative Aptitude is a separate timed section, reported for 2026 as 40 questions for 50 marks in 35 minutes. It has more data interpretation and arithmetic, with less friendly numbers. The skills are the same: fast, accurate calculation and good choices.

What the section usually contains

Clerk prelims numerical sections have tended to follow a recognisable shape: a block of simplification or approximation, a block of number series, one or two DI sets, and a handful of arithmetic word problems. The exact counts change from year to year, so look at the latest memory-based papers once you have covered the basics.

Simplification and approximation matter most in the clerk prelims for two reasons. They usually form a sizeable block, and they are the most trainable types: daily drills improve them within weeks.

A time budget for 20 minutes

If you finish the calculation block in about 7 minutes and the series in about 3, you have 10 minutes for one DI set and several arithmetic questions. That is a realistic plan for a good score.

A six-week order

Keep the daily drills going all six weeks. A topic "finished" in week 1 is forgotten by week 6 if you stop practising it.

Daily drills (15–20 minutes)

• Tables and squares aloud: tables to 30, squares to 50.
• Ten simplification questions with a 4-minute timer.
• Five approximation questions in 2 minutes.
• Three number series in 90 seconds.
• Fraction–percentage pairs: 1/6 = 16.67%, 1/7 ≈ 14.29%, 1/8 = 12.5%, 3/8 = 37.5%, 1/9 ≈ 11.11%, 1/12 ≈ 8.33%.

One worked question of each key type

1. Simplification. 35% of 240 + 3/5 of 185 = ?

1. 35% of 240: 10% is 24, so 30% is 72 and 5% is 12. Total 84.
2. 3/5 of 185: 185 ÷ 5 = 37, and 37 × 3 = 111.
3. 84 + 111 = 195.

2. Approximation. 64.98% of 719.8 + 11.97 × 8.02 ≈ ?

1. Round: 65% of 720 + 12 × 8.
2. 65% of 720 = 720 × 0.65 = 468. (10% is 72; 60% is 432; 5% is 36.)
3. 12 × 8 = 96, so the total is 468 + 96 = 564.

3. Number series. 5, 9, 17, 33, 65, ?

1. The terms almost double, so test multiplication.
2. 5 × 2 − 1 = 9, 9 × 2 − 1 = 17, 17 × 2 − 1 = 33, 33 × 2 − 1 = 65. The rule fits four steps.
3. 65 × 2 − 1 = 129.

4. Data interpretation. Three branches opened savings accounts in a month: A 240, B 180, C 300.

1. B as a percentage of C = 180 ÷ 300 × 100 = 60%.
2. Average per branch = (240 + 180 + 300) ÷ 3 = 720 ÷ 3 = 240.
3. By what percentage does C exceed B? (300 − 180) ÷ 180 × 100 = 120 ÷ 180 × 100 = 66.67%. The base is B, the number you compare against.

5. Profit and loss. An article marked at ₹800 is sold at a 15% discount. The cost price is ₹600. Find the profit percentage.

1. Selling price = 800 × 0.85 = ₹680.
2. Profit = 680 − 600 = ₹80.
3. Profit % = 80 ÷ 600 × 100 = 13⅓%. Profit is always on cost price, not on marked price.

6. Ratio. A : B = 3 : 5 and B : C = 4 : 7. Find A : B : C.

1. B is 5 in the first ratio and 4 in the second. Make it 20 in both.
2. Multiply the first by 4: 12 : 20. Multiply the second by 5: 20 : 35.
3. A : B : C = 12 : 20 : 35.

Question selection in the exam

1. Scan the section first (10–15 seconds). Find the simplification, approximation and series blocks.
2. Do the calculation block first. These are the quickest marks.
3. Then the series, with a hard limit of about 40 seconds each.
4. Then one DI set whose chart and numbers look clean.
5. Then arithmetic, only the types you recognise immediately. Leave long, many-step word problems for the last minutes, or leave them.

Other common mistakes

• Calculating exactly in approximation questions.
• Ignoring DI in the prelims. One clean set can give four or five marks in a few minutes.
• Taking percentages on the wrong base, as in example 4.
• Stopping daily drills once the topics feel finished.

Practice

1. 48 × 25
2. 15² + 12² − 9²
3. 1/8 of 1,000 + 37.5% of 400
4. 7, 12, 22, 37, 57, ?
5. 399.8 ÷ 20.1 × 14.9 ≈ ?
6. The average of 24, 36, 42 and 58
7. Simple interest on ₹5,000 at 8% a year for 3 years
8. The price of rice rises by 25%. By what percentage must a family cut consumption to keep spending the same?

Answers:

1. 1,200. 48 × 100 ÷ 4 = 4,800 ÷ 4.
2. 288. 225 + 144 − 81.
3. 275. 125 + 150; 37.5% is 3/8, and 3/8 of 400 = 150.
4. 82. Differences 5, 10, 15, 20, so next is 25; 57 + 25.
5. 300 (approximately). 400 ÷ 20 × 15 = 20 × 15.
6. 40. Sum 160 ÷ 4.
7. ₹1,200. 5,000 × 8 × 3 ÷ 100.
8. 20%. Cut = 25 ÷ (100 + 25) × 100 = 25 ÷ 125 × 100.

What to do next

• Start the 15-minute daily drill today and log your time for ten simplification questions.
• Work through the simplification, approximation and number series guides in weeks 1–3.
• From week 3, take one 20-minute sectional test every other day and note which types you skipped.