Defence | CDS

Mathematics for CDS

CDS sets 100 Mathematics questions for 100 marks in the Written Examination (IMA, INA and AFA), so it is worth planning your preparation around the topics below.

100 questions100 marks5 topics

How to approach Mathematics in CDS

The quantitative core of the railway papers: arithmetic, mensuration, and time-speed-distance built on a secondary-school foundation. Fluency with fractions, percentages and ratios underlies almost every question, so that is where practice pays back fastest.

Weightage in the paper

How much Mathematics is worth in each CDS stage, from the official pattern.

Stage	Questions	Marks	Time	Share
Written Examination (IMA, INA and AFA)	100	100	—	29%

Mathematics syllabus for CDS

Every topic in the official syllabus. The linked ones open a set of solved questions you can practise straight away.

Arithmetic: number system, HCF/LCM, percentage, ratio, average, interest
Algebra and basic set theory
Trigonometry
Geometry and mensuration
Statistics: mean, median, mode and graphs

Sample Mathematics questions with solutions

Written to the CDS pattern, with the answer key and the method behind it — a look at how the section is actually set before you drill the full topic sets.

Number series · solved example

Find the next term: 5, 11, 23, 47, ?

94
96
95Correct
93

Solution

Each term is double the previous plus one: 5×2+1 = 11, 11×2+1 = 23, 23×2+1 = 47, and 47×2+1 = 95.

Percentage · solved example

Find 20% of 640.

133
148
108
123
128Correct

Solution

20% means 20/100, so 20% of 640 = 128.

Simple interest · solved example

A sum of Rupees 8,000 amounts to Rupees 9,440 in 2 years under simple interest. What is the rate of interest per annum?

8%
9%Correct
10%
12%

Solution

The interest earned is 9440 - 8000 = 1440 rupees over 2 years. Using rate = interest x 100 / (principal x time), we get 1440 x 100 / (8000 x 2) = 144000/16000 = 9%. A quick check: 9% of 8000 is 720 a year, and 720 x 2 = 1440, which matches.

Time and work · solved example

6 workers finish a task in 10 days. How many days will 5 workers take at the same rate?

12Correct
17
7
5
19

Solution

The work is 10×6 = 60 worker-days, so 5 workers take 60/5 = 12 days.

Sit Mathematics under a real clock

Mathematics shows up in every CDS mock test, in the same interface, with sectional locking and negative marking.

CDS: 27-question practice mock
27 questions | 27 min
Start

Frequently asked questions

How many Mathematics questions are asked in CDS?

CDS 2026 cycle sets 100 Mathematics questions for 100 marks in the Written Examination (IMA, INA and AFA).

Is there negative marking for Mathematics in CDS?

Yes. CDS deducts one third of a mark for each wrong answer, Mathematics included, so unsure guesses cost you. One third of the marks assigned to a question is deducted for each wrong answer. Unanswered questions carry no penalty.

Which Mathematics topics matter most for CDS?

The CDS syllabus lists Arithmetic: number system, HCF/LCM, percentage, ratio, average, interest, Algebra and basic set theory, Trigonometry, Geometry and mensuration, Statistics: mean, median, mode and graphs. Weight your revision towards the ones you are weakest on and confirm the emphasis against the paper analysis for recent cycles.

How can I practise Mathematics for CDS free?

Every Mathematics question on this site is free and written to the exam pattern. Use the topic drills for instant-feedback practice, the daily quiz to keep the section warm, and the CDS mock tests to sit it under a real clock with negative marking.