This section is about the most fundamental topics in mathematics: **Number System**. What is maths all about? Numbers, off course. This unit of the website is all about numbers. Starting from absolute basics, this section provides you all the material you need to study the topic: concepts, articles, blogs and tests. Make sure you go through each and every piece in the order provided.

How to use this section? We have simple piece of advice for you: Start with articles (provided in the index) and read them one at a time. Once you are through with an article, solve the topic tests corresponding to that topic. Once you are done with all the articles and the tests, head over to the level-wise tests. Geez, do all this work and you will be a master of the topic.

**Number System for CAT 2021 : Concepts and Fundamentals**

Prime Numbers and Composite Numbers

Properties of Addition of Natural Numbers

Properties of Consecutive Integers

Divisibility Rules explained with examples

H.C.F. by Long Division Method

Application of Concept of Cyclicity

How to find the Unit Digit of a number

Highest Power of a prime in a Factorial

Number of zeros at the end of a factorial

Extra Problems for ‘Number of Zeros’

**Number System for CAT 2021 : Topic Wise Tests**

**Each test-name highlights the area of the test. Select the topic you wish to practice. **

No. System: Decimals/Fractions Test-1

No. System: Decimals/Fractions Test-2

No. System: LCM and HCF Test-2

No. System: LCM and HCF Test-3

No. System: LCM and HCF Test-4

No. System: Basics of Factors Test-1

No. System: Basics of Factors Test-2

No. System: Basics of Factors Test-3

No. System: Basics of Factors Test-4

No. System: Factorials & No. of Zeros Test-1