SSC GD Formula Sheet
Ten formulas, what each one is for, and a worked example.
SSC GD's Elementary Mathematics section is pitched at class 10. It covers number system, percentages, ratio, averages, interest, profit and loss, discount, time and work, speed and simple mensuration.
These ten formulas cover the section, with a worked simple-interest example.
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The 10 Formulas
1
Formula
HCF × LCM
Expression
HCF × LCM = Product of the two numbers
Use it for
Finding a missing number from its HCF and LCM.
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
Dividing in a ratio
Expression
Share of A = Total × a ÷ (a + b)
Use it for
Splitting an amount, profit or quantity in a ratio.
4
Formula
Average
Expression
Sum of observations ÷ Number of observations
Use it for
Averages, and finding a missing or replaced value.
5
Formula
Simple interest
Expression
SI = P × R × T ÷ 100
Use it for
Interest that isn't added back to the principal.
6
Formula
Profit %
Expression
(SP − CP) ÷ CP × 100
Use it for
Profit or loss on cost price.
7
Formula
Discount and marked price
Expression
SP = MP × (1 − Discount/100)
Use it for
Selling price after a discount on the marked price.
8
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.
9
Formula
Speed, distance, time
Expression
Distance = Speed × Time; km/h × 5/18 = m/s
Use it for
Trains, journeys and unit conversions.
10
Formula
Circle
Expression
Area = πr²; Circumference = 2πr
Use it for
Mensuration questions on wheels, tracks and plots.
| # | Formula | Expression | Use it for |
|---|---|---|---|
| 1 | HCF × LCM | HCF × LCM = Product of the two numbers | Finding a missing number from its HCF and LCM. |
| 2 | Percentage change | (New − Old) ÷ Old × 100 | Growth and fall in values, and the base of most DI questions. |
| 3 | Dividing in a ratio | Share of A = Total × a ÷ (a + b) | Splitting an amount, profit or quantity in a ratio. |
| 4 | Average | Sum of observations ÷ Number of observations | Averages, and finding a missing or replaced value. |
| 5 | Simple interest | SI = P × R × T ÷ 100 | Interest that isn't added back to the principal. |
| 6 | Profit % | (SP − CP) ÷ CP × 100 | Profit or loss on cost price. |
| 7 | Discount and marked price | SP = MP × (1 − Discount/100) | Selling price after a discount on the marked price. |
| 8 | Time and work (two people) | Days together = (a × b) ÷ (a + b) | When A alone takes a days and B alone takes b days. |
| 9 | Speed, distance, time | Distance = Speed × Time; km/h × 5/18 = m/s | Trains, journeys and unit conversions. |
| 10 | Circle | Area = πr²; Circumference = 2πr | Mensuration questions on wheels, tracks and plots. |
Worked Example: Simple Interest
Find the simple interest on ₹5,000 at 8% a year for 3 years.
- 1
Apply SI = P × R × T ÷ 100
5,000 × 8 × 3 ÷ 100.
- 2
Calculate
₹1,200.
- 3
Amount
5,000 + 1,200 = ₹6,200 at the end.
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Elementary Doesn't Mean Careless
The maths is easy, but GD is a speed test with negative marking. Read units and what is asked (interest or amount, profit or selling price) before choosing.
FAQs
How many maths questions are in SSC GD?expand_more
Elementary Mathematics is one of four sections in the computer-based exam. Check the current notice for the exact count.
Is there negative marking?expand_more
Yes, SSC GD deducts marks for wrong answers. Check the current notice for the fraction.
Which value of π should I use?expand_more
Use 22/7 unless the question gives 3.14.
Next steps
Take a full SSC GD mock testThe whole CBT syllabus in one timed, scored paper.