Important Mathematics Topics and Tips for Combined Defence Services Exam

For admission of qualified candidates to the Indian Military Academy (IMA), Indian Naval Academy (INA), Air Force Academy (AFA), Officers’ Training Academy (OTA), the Union Public Service Commission (UPSC) conducts the Combined Defence Services exam twice a year.

Among three sections in the CDS exam i.e., Elementary Mathematics, English, and General Knowledge, the Mathematics section comprises 100 objective-type questions making a total of 100 marks. This makes it a game-changer for candidates in the exam, especially for those who were not able to follow General Knowledge rigorously, then mathematics paper can be an exam savior.

On that note, read ahead to know about a few important mathematics topics and tricks that can fetch you a good score in the mathematics section of the upcoming CDS exam.

Important Maths Topics for CDS Exam

Number System

15 to 20 questions can be asked from this part from topics like Surds and Indices, L.C.M. & H.C.F., simplification, remainder theorem and others.

  • To grasp the basic concepts of these topics, one might refer to the NCERT textbook from classes 9 to 12. You can also refer to comprehensive maths books like quantitative aptitude for competitive exams by RS Agarwal.
  • LCM/ HCF and Remainder questions are frequently asked in the exam. As a result, it’s a good idea to learn how to solve these questions correctly, look for any useful shortcuts, and extensively practise these topics before the exam.
  • Understanding the basics of the highest common factor (HCF) and lowest common multiples (LCM), as well as the relationship between HCF and LCM of two numbers, is essential.


Questions in the arithmetic part are asked from Time, Speed and Distance, Percentages, Ratio and Proportion, Time and Work, Simple and Compound Interest and so on.

Since a few of these topics like percentage, average, ratio and proportion form the base of your mathematics preparation, you are advised to have a sound understanding of concepts in these topics and practice an ample number of questions in them.

Let’s talk about the remaining important topics and how to prepare them.

Speed, Distance and Time

A basic understanding of speed, time, and distance is required, with a focus on units of measurement and their conversion in Time, Speed, and Distance.

Time and work

You should be familiar with LCM, the Unitary method, and other computations in order to answer these problems.

Simple and Compound Interest

The application of basic SI, CI, and Amount formulas is generally required in questions from this area.

Profit and Loss

If the product is continuously bought and sold among different people, the phrasing of the query can make it difficult to determine the Cost Price (CP) and Selling Price (SP).


As per the analysis of previous years’ papers, you can expect at least 10 to 11 questions from this part in the CDS written exam. Let’s break down topics and tips to prepare them under this part.

The following topics will be covered in Algebra questions:

Quadratic equation

Practice enough standard questions on two-degree quadratic equations, the sum and product of roots as they are frequently asked.

Simultaneous Equations

Solve simultaneous equations involving two variables and practical problems.

Set Theory

Learn union and intersection theorems and their application in practical cases.

Indices and logarithm

These topics are connected and can be studied together.


Prepare the trigonometric ratios, quadrants, and trigonometric identities.

The application of trigonometric concepts to practical situations in the form of is a common question.


Once done with , move on to simple geometry, where you will have to learn about properties of lines, angles between lines and properties of various two-dimensional basic shapes.


Questions of this topic may involve finding the area and perimeter of two-dimensional shapes as well as the surface area and volume of different three-dimensional shapes. Be thorough with various formulas and practice different types of questions of associated shapes. For more: Important mathematics topics for cds exam Click Here

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