In this guide
For many SSC GD aspirants, maths is the section they fear most. Here is the good news: the maths is Class 10 level, and the same kinds of question come again and again. With 45 to 60 minutes of daily practice, most candidates can go from avoiding maths to scoring well in it within about six weeks.
Maths is also the slowest section in the paper. That is why method matters more than memory here. If you know the method well, each question takes under a minute. If you don't, a single question can eat three.
Weightage
- 20 questions, 40 marks, the same as every other section.
- 2 marks for a right answer, 0.25 deducted for a wrong one (as reported).
- A sensible time share is about 18–20 minutes of the 60, which is roughly one minute per question.
Topics and priority
| Topic | Our priority | Why |
|---|---|---|
| Percentage | Very high | Used inside profit, discount, interest and more |
| Ratio and proportion | Very high | Used in ages, partnership, mixtures |
| Average | High | Quick marks once the method is clear |
| Profit, loss and discount | High | Direct percentage use |
| Simple and compound interest | High | Formula-based, predictable |
| Time and work | Medium | One method (the LCM or fraction method) covers most questions |
| Time and distance | Medium | Unit conversion is the main trap |
| Number system, LCM and HCF | Medium | Short, rule-based questions |
| Simplification, fractions, decimals | Medium | Needs BODMAS and fast calculation |
| Mensuration | Medium | Area and volume formulas |
The priority is our judgement of how much each topic helps, not an official weightage.
A six-week order
| Week | Topics |
|---|---|
| 1 | Tables, squares, fractions; number system; simplification (BODMAS) |
| 2 | LCM and HCF; percentage |
| 3 | Ratio; average; ages |
| 4 | Profit, loss and discount |
| 5 | Simple and compound interest; time and work |
| 6 | Time and distance; mensuration; mixed practice |
Percentage comes in week 2 on purpose. Weeks 3 to 5 all lean on it.
A daily routine (45–60 minutes)
- 10 minutes: tables, squares and quick mental sums.
- 25 minutes: one topic. Learn the method from two solved examples, then do 20 questions.
- 10 minutes: 10 mixed questions from earlier topics, so you don't forget them.
- 5 minutes: write today's mistakes in your error notebook.
Number facts to learn by heart
- Tables up to 20.
- Squares up to 30 (for example 13² = 169, 17² = 289, 25² = 625).
- Cubes up to 15 (for example 12³ = 1,728, 15³ = 3,375).
- Fraction–percentage pairs:
| Fraction | Percentage | Fraction | Percentage |
|---|---|---|---|
| 1/2 | 50% | 1/6 | 16⅔% |
| 1/3 | 33⅓% | 1/8 | 12.5% |
| 1/4 | 25% | 1/10 | 10% |
| 1/5 | 20% | 3/4 | 75% |
- Speed conversion: km/h to m/s, multiply by 5/18. m/s to km/h, multiply by 18/5.
Six solved examples
Example 1 (percentage). A number increased by 25% becomes 150. Find the number.
- An increase of 25% means the new value is 125% of the old, or 1.25 times.
- Number × 1.25 = 150.
- Number = 150 ÷ 1.25 = 120.
- Check: 25% of 120 = 30, and 120 + 30 = 150.
Example 2 (ratio). Divide ₹1,200 between two people in the ratio 3 : 5.
- Total parts = 3 + 5 = 8.
- One part = 1,200 ÷ 8 = ₹150.
- Shares: 3 × 150 = ₹450 and 5 × 150 = ₹750.
Example 3 (average). The average of five numbers is 24. When one number is removed, the average of the other four is 22. Which number was removed?
- Sum of five = 5 × 24 = 120.
- Sum of four = 4 × 22 = 88.
- Removed number = 120 − 88 = 32.
Example 4 (profit). An article bought for ₹640 is sold at a 15% profit. Find the selling price.
- Profit = 15% of 640 = 640 × 15 ÷ 100 = ₹96.
- Selling price = 640 + 96 = ₹736.
- Shortcut: 640 × 1.15 = 736.
Example 5 (simple interest). Find the simple interest on ₹5,000 at 8% a year for 3 years.
- SI = Principal × Rate × Time ÷ 100.
- SI = 5,000 × 8 × 3 ÷ 100 = 1,20,000 ÷ 100 = ₹1,200.
Example 6 (speed). A train 300 m long runs at 54 km/h. How long does it take to pass a pole?
- Convert speed: 54 × 5/18 = 15 m/s.
- To pass a pole, the train covers its own length, 300 m.
- Time = 300 ÷ 15 = 20 seconds.
Common errors
| Error | Example | Fix |
|---|---|---|
| Percentage of the wrong base | Taking profit % on selling price | Profit and loss % are on cost price unless stated |
| Mixing units | km/h with metres | Convert before you calculate |
| Adding percentages across steps | +20% then −20% taken as 0 | Work with a base of 100 |
| Rushing easy steps | 8 × 7 = 54 | Say the table in your head; check the last line |
Our guide to common maths mistakes covers these in more detail.
Practice set
- Find 35% of 240.
- Divide ₹2,100 in the ratio 2 : 5.
- Find the average of the first five multiples of 6.
- An article bought for ₹450 is sold for ₹540. Find the profit percentage.
- Find the simple interest on ₹3,000 at 6% a year for 2 years.
- A can finish a job in 12 days and B in 24 days. How long will they take together?
- Convert 72 km/h into m/s.
- A bag marked ₹900 is sold at a 20% discount. Find the selling price.
Answers:
- 240 × 35 ÷ 100 = 84.
- 7 parts; one part = 300; shares ₹600 and ₹1,500.
- 6, 12, 18, 24, 30; sum 90; 90 ÷ 5 = 18.
- Profit = 90; 90 ÷ 450 × 100 = 20%.
- 3,000 × 6 × 2 ÷ 100 = ₹360.
- Work per day = 1/12 + 1/24 = 2/24 + 1/24 = 3/24 = 1/8, so 8 days.
- 72 × 5/18 = 20 m/s.
- 20% of 900 = 180; 900 − 180 = ₹720.
Self-check after six weeks
- I know tables to 20, squares to 30 and cubes to 15.
- I can solve a basic percentage or ratio question in under 45 seconds.
- I have practised every topic in the six-week table at least once.
- My accuracy on 20 mixed questions is above 80%.
- My error notebook has fewer new entries each week.
A note on dates and numbers. Exam patterns, vacancies and schedules change from year to year. Always confirm the current details in the latest notification on the Staff Selection Commission website .
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