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How can I improve my calculation speed for SBI Clerk?

Section strategyUpdated 2026-10-23
Short answer

Memorise tables to 20, squares to 30, cubes to 20 and common fraction-percentage values, then do a timed 15-20 minute simplification drill every day. Speed comes from daily repetition, not from more tricks.

Calculation speed is a memory and practice problem. Quant Prelims gives you 20 minutes for 35 questions, which is about 34 seconds a question. You cannot spend 15 of those seconds multiplying 17 by 23 on paper.

What to memorise first

ItemRangeUsed in
Multiplication tablesup to 20Everything
Squares1 to 30Simplification, quadratic, series
Cubes1 to 20Simplification, series
Fraction to percent1/2 to 1/20Percentage, profit and loss, DI

Useful fraction values: 1/8 = 12.5%, 1/6 = 16.67%, 1/7 = 14.29%, 1/9 = 11.11%, 1/11 = 9.09%, 1/12 = 8.33%, 1/16 = 6.25%.

Mental shortcuts worth learning

  • Multiply by 5: multiply by 10 and halve. 48 × 5 = 480 ÷ 2 = 240.
  • Multiply by 25: multiply by 100 and divide by 4. 36 × 25 = 3600 ÷ 4 = 900.
  • Multiply by 11 (two digits): put the sum of the digits in the middle. 43 × 11 = 4(4+3)3 = 473.
  • Percent of a number: 18% of 450 = 10% (45) + 8% (36) = 81.
  • Unit digit check: before calculating fully, look at the last digit of each option. Often only one option fits.

The daily drill

  1. 15-20 simplification questions with a timer, every morning.
  2. Note your time and accuracy. Aim to bring average time per question down week by week.
  3. Write fewer steps. Do intermediate results in your head and write only what you would forget.
Look at the options before you calculate. If they are far apart, an approximate answer is enough; if they are close, calculate exactly.
No calculator is allowed in the exam, and rough sheets are provided at the centre. Practise on plain paper, not on a phone calculator.

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