SBI Clerk Formula Sheet
Ten formulas, what each one is for, and a worked example.
SBI Clerk Prelims gives about 20 minutes for 35 Numerical Ability questions, so speed decides the score. Most questions are simplification, approximation and short arithmetic problems.
These ten formulas and shortcuts cover the arithmetic, with a worked CI vs SI example.
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The 10 Formulas
1
Formula
BODMAS order
Expression
Brackets → Of → Division → Multiplication → Addition → Subtraction
Use it for
Simplification questions, the biggest block in Prelims.
2
Formula
Percentage change
Expression
(New − Old) ÷ Old × 100
Use it for
Growth and fall in values, and the base of most DI questions.
3
Formula
Profit %
Expression
(SP − CP) ÷ CP × 100
Use it for
Profit or loss on cost price.
4
Formula
Simple interest
Expression
SI = P × R × T ÷ 100
Use it for
Interest that isn't added back to the principal.
5
Formula
Compound interest
Expression
A = P × (1 + R/100)ᵀ; CI = A − P
Use it for
Interest compounded once a year.
6
Formula
CI − SI for 2 years
Expression
P × (R/100)²
Use it for
The one-line shortcut for the 2-year difference.
7
Formula
Average
Expression
Sum of observations ÷ Number of observations
Use it for
Averages, and finding a missing or replaced value.
8
Formula
Dividing in a ratio
Expression
Share of A = Total × a ÷ (a + b)
Use it for
Splitting an amount, profit or quantity in a ratio.
9
Formula
Problems on ages
Expression
Write both ages now as x and y, then shift both by the same number of years
Use it for
Age-ratio questions: both ages change by the same amount.
10
Formula
Time and work (two people)
Expression
Days together = (a × b) ÷ (a + b)
Use it for
When A alone takes a days and B alone takes b days.
| # | Formula | Expression | Use it for |
|---|---|---|---|
| 1 | BODMAS order | Brackets → Of → Division → Multiplication → Addition → Subtraction | Simplification questions, the biggest block in Prelims. |
| 2 | Percentage change | (New − Old) ÷ Old × 100 | Growth and fall in values, and the base of most DI questions. |
| 3 | Profit % | (SP − CP) ÷ CP × 100 | Profit or loss on cost price. |
| 4 | Simple interest | SI = P × R × T ÷ 100 | Interest that isn't added back to the principal. |
| 5 | Compound interest | A = P × (1 + R/100)ᵀ; CI = A − P | Interest compounded once a year. |
| 6 | CI − SI for 2 years | P × (R/100)² | The one-line shortcut for the 2-year difference. |
| 7 | Average | Sum of observations ÷ Number of observations | Averages, and finding a missing or replaced value. |
| 8 | Dividing in a ratio | Share of A = Total × a ÷ (a + b) | Splitting an amount, profit or quantity in a ratio. |
| 9 | Problems on ages | Write both ages now as x and y, then shift both by the same number of years | Age-ratio questions: both ages change by the same amount. |
| 10 | Time and work (two people) | Days together = (a × b) ÷ (a + b) | When A alone takes a days and B alone takes b days. |
Worked Example: CI − SI Shortcut
Find the difference between compound and simple interest on ₹10,000 at 10% for 2 years.
- 1
Use the shortcut
Difference = P × (R/100)².
- 2
Substitute
10,000 × (0.10)² = 10,000 × 0.01.
- 3
Answer
₹100, without working out either interest.
Questions from this exact syllabus. No signup.
Memorise Squares and Fractions
Simplification is about mental arithmetic. Knowing squares up to 30, cubes up to 15 and fraction-to-percentage conversions (1/8 = 12.5%) saves more time than any formula.
FAQs
How many maths questions are in SBI Clerk Prelims?expand_more
35 Numerical Ability questions, in a 20-minute section.
Is DI asked in SBI Clerk?expand_more
Mainly in Mains Quantitative Aptitude. Prelims is mostly simplification and arithmetic.
What is approximation?expand_more
Questions where you round the numbers and pick the closest option, rather than calculate exactly.
Next steps
Take a full SBI Clerk mock testThe whole syllabus, timed and scored like the real paper.