SSC CHSL 2026 maths preparation: formula sheet, topics and a 15-minute plan
SSC CHSL Tier-I Quantitative Aptitude is 25 questions worth 50 marks, done in its own 15-minute window, with 2 marks for a right answer and 0.50 taken off for a wrong one. The notice calls it "Basic Arithmetic Skill": mostly Class 10 arithmetic that a good formula sheet turns into a line or two of working. Learn the formulas below until they are automatic, do arithmetic first, then algebra, trigonometry and mensuration, and practise in timed sets of 25. Tier-I is proposed for 30 November to 31 December 2026; dates and how to apply are in our SSC CHSL 2026 guide.
What the notice lists for Quantitative Aptitude
Paragraph 13.10.3 of the SSC CHSL 2026 notice gives the Tier-I maths syllabus:
| Area | Topics in the notice |
|---|---|
| Number systems | Whole numbers, decimals and fractions, relationships between numbers |
| Arithmetic | Percentages, ratio and proportion, square roots, averages, simple and compound interest, profit and loss, discount, partnership, mixture and alligation, time and distance, time and work |
| Algebra | Basic identities of school algebra, elementary surds, graphs of linear equations |
| Geometry | Triangles and their centres, congruence and similarity, circles, chords, tangents, angles subtended by chords, common tangents |
| Mensuration | Triangle, quadrilaterals, regular polygons, circle, prism, cone, cylinder, sphere, hemisphere, cuboid, pyramid |
| Trigonometry | Ratios, complementary angles, standard identities, simple heights and distances |
| Statistical charts | Tables, histogram, frequency polygon, bar diagram, pie chart |
Questions come in English and Hindi. Tier-II Mathematical Abilities repeats this list, so the work counts twice.
Formula sheet with worked examples
Percentages
- Fractions to know by heart: 1/2 = 50%, 1/3 = 33.33%, 1/4 = 25%, 1/5 = 20%, 1/6 = 16.67%, 1/8 = 12.5%, 1/9 = 11.11%, 1/12 = 8.33%.
- Two changes of a% and b% one after the other: net change = a + b + ab/100.
Example: a price rises 20% and then falls 20%. Net change = 20 − 20 + (20 × −20)/100 = −4%, a 4% fall.
Profit, loss and discount
- Profit % = profit/CP × 100. SP = CP × (100 + profit%)/100.
- Discount is always on the marked price (MP). SP = MP × (100 − discount%)/100.
- To earn P% profit after giving D% discount: MP = CP × (100 + P)/(100 − D).
Example: an article costs ₹300. To make 20% profit after a 10% discount, MP = 300 × 120/90 = ₹400.
Simple and compound interest
- SI = P × R × T/100.
- Amount with CI = P(1 + R/100)^T.
- For 2 years, CI − SI = P(R/100)².
Example: ₹10,000 at 10% for 2 years. SI = ₹2,000. Amount with CI = 10,000 × 1.1 × 1.1 = ₹12,100, so CI = ₹2,100.
Ratio, proportion and partnership
- To join A:B and B:C, make B equal in both.
Example: A:B = 2:3 and B:C = 4:5. Multiply the first by 4 and the second by 3: A:B:C = 8:12:15.
Averages and alligation
- Sum = average × count. A new value = new sum − old sum.
- Alligation: mixing two kinds at prices c and d to get mean m, the ratio is (d − m):(m − c).
Example: the average of 5 numbers is 40. A sixth number makes it 42. The sixth number = 6 × 42 − 5 × 40 = 252 − 200 = 52.
Time and work
- Take total work as the LCM of the days; each person's daily work is total ÷ their days.
Example: A finishes a job in 12 days and B in 18. Total work = 36 units; A does 3 a day, B does 2. Together: 36 ÷ 5 = 7.2 days.
Time, speed and distance
- km/h to m/s: multiply by 5/18. 72 km/h = 20 m/s.
- Average speed over two equal distances: 2xy/(x + y).
- A train passing a pole covers its own length; passing a platform covers train + platform.
Example: a 200 m train at 72 km/h passes a pole in 200 ÷ 20 = 10 seconds and a 300 m platform in 500 ÷ 20 = 25 seconds. Going at 40 km/h and returning at 60 km/h gives an average of 2 × 40 × 60/100 = 48 km/h.
Mensuration
| Shape | Area or volume | Surface |
|---|---|---|
| Equilateral triangle, side a | (√3/4)a² | perimeter 3a |
| Circle, radius r | πr² | circumference 2πr |
| Cuboid l, b, h | lbh | 2(lb + bh + hl) |
| Cube, side a | a³ | 6a² |
| Cylinder | πr²h | curved 2πrh |
| Cone, slant l | (1/3)πr²h | curved πrl |
| Sphere | (4/3)πr³ | 4πr² |
| Hemisphere | (2/3)πr³ | total 3πr² |
Example: a cylinder with r = 7 cm and h = 10 cm holds 22/7 × 49 × 10 = 1,540 cm³.
Trigonometry
| 0° | 30° | 45° | 60° | 90° | |
|---|---|---|---|---|---|
| sin | 0 | 1/2 | 1/√2 | √3/2 | 1 |
| cos | 1 | √3/2 | 1/√2 | 1/2 | 0 |
| tan | 0 | 1/√3 | 1 | √3 | not defined |
- sin²θ + cos²θ = 1, 1 + tan²θ = sec²θ, 1 + cot²θ = cosec²θ.
- sin(90° − θ) = cos θ, tan(90° − θ) = cot θ.
Example: the top of a tower is seen at 60° from a point 10 m from its foot. Height = 10 × tan 60° = 10√3 m.
Algebra identities
- (a + b)² = a² + 2ab + b²; (a − b)² = a² − 2ab + b²; a² − b² = (a + b)(a − b).
- (a + b)³ = a³ + b³ + 3ab(a + b); a³ + b³ = (a + b)(a² − ab + b²).
- a³ + b³ + c³ − 3abc = (a + b + c)(a² + b² + c² − ab − bc − ca); if a + b + c = 0, a³ + b³ + c³ = 3abc.
Example: if x + 1/x = 3, then x² + 1/x² = 3² − 2 = 7, and x³ + 1/x³ = 3³ − 3 × 3 = 18.
Geometry facts that answer questions directly
- Centroid divides each median 2:1; angle in a semicircle is 90°; tangent ⊥ radius at the point of contact.
- Interior angles of an n-sided polygon: (n − 2) × 180°.
Which topics to do first
- Percentages, ratio and averages. They are tools inside almost every other topic.
- Profit and loss, discount, interest. Direct use of the percentage formulas.
- Time and work, time and distance. One method each (LCM units, the 5/18 conversion).
- Number system and simplification. Quick marks if your calculation is clean.
- Mensuration and trigonometry. Mostly formula and table recall.
- Algebra identities and geometry. Learn the identities above and the common results.
- Statistical charts. Read the chart once and answer all its questions.
Short of time? The first four groups give the most questions per hour of study, and trigonometry values take a minute to learn.
How to finish 25 questions in 15 minutes
Fifteen minutes for 25 questions is 36 seconds each, so plan in rounds:
- Round 1 (about 9 minutes): go through all 25 in order. Answer every question you can do in under 40 seconds. If the method is not clear in 10 seconds, mark it for review and move on.
- Round 2 (about 5 minutes): return to the marked questions that need a longer calculation you know how to do.
- Last minute: stop starting new work. Check one or two answers you were unsure of.
Ways to save seconds:
- Read the options first; if they are far apart, round the numbers.
- Use the units method (LCM) for work and the fraction table for percentages instead of writing out equations.
- In algebra, put a simple value (like x = 1 or a = 0) into the expression and test the options.
With +2 and −0.5, a wrong answer costs a quarter of a right one. If you can rule out two options, a guess is worth taking; our negative marking article works this out, and how many questions to attempt looks at targets.
Our free SSC CHSL mock tests run the real 15-minute section timers in English and Hindi and show which maths topics to practise next.
Useful links
- SSC CHSL 2026 notice (PDF, ssc.gov.in), paragraph 13.10.3 for the syllabus
- Free SSC CHSL mock tests
- SSC CHSL syllabus
- SSC CHSL 2026: exam date, pattern and how to apply
- SSC CHSL Tier-I preparation strategy
- SSC CHSL reasoning preparation
Frequently asked questions
How many maths questions are there in SSC CHSL Tier-I?
25 questions for 50 marks, in a 15-minute section of their own. A right answer gets 2 marks and a wrong one loses 0.50.
Is SSC CHSL maths hard?
The notice calls it "Basic Arithmetic Skill". The level is Class 10; the difficulty is mostly speed, since you have about 36 seconds a question.
Which topics are most important for SSC CHSL maths?
Start with percentages, ratio, averages, profit and loss, interest, time and work and time and distance. Then mensuration, trigonometry, algebra identities, geometry and charts. All are in the notice, so none can be ignored completely.
Is trigonometry in SSC CHSL Tier-I?
Yes. The notice lists trigonometric ratios, complementary angles, standard identities and simple heights and distances.