Number System Class 9 Chapter 1 Quiz / Multiple Choice Questions


This Maths quiz is based on Class 9 Chapter-1. The name of the chapter is Number System / Rational and Irrational Numbers. The chapter contains many sums and rules which clearly explain the difference between Rational and Irrational numbers. The main concepts included in this online quiz or multiple choice based questions are:

  • Repeating, non-repeating decimals
  • Terminating, non terminating decimals. Numbers between two rational or irrational numbers
  • The decimal representation of a rational number
  • The distinction between rational and irrational numbers.
  • comparing two irrational numbers
  • conversion of decimal numbers into rational numbers of the form m/n

Important Definitions and explanations of the chapter- Number System

Rational numbers: 

A number is a rational number if it can be written in the form p/q where p and q are co-prime numbers and q≠0. A number is also called a rational number if it has either terminating or non-terminating and repeating decimal representation.

Irrational Numbers: 

A number is an irrational number if it has a non-terminating and non-repeating decimal representation.

Real Numbers: 

All the rational and irrational numbers taken together make Real numbers.

Terminating/Finite Decimals: 

The rational numbers with a finite decimal part or for which the long division terminates after a finite number of steps are known as finite or terminating decimals.

Some important theorems on Irrational Numbers

The following are some useful results on irrational numbers. We can also call them Theorems.

Theorem 1: 

Negative of an irrational number is an irrational number.

Theorem 2: 

The sum of a rational number and an irrational number is an irrational number.

Theorem 3: 

The product of a non-zero rational number and an irrational number is an irrational number.

Theorem 4: 

The sum, difference, product and quotient of two irrational numbers need not be an irrational number, because


(i) The sum of √2 and -√2 is 0, which is a rational number, whereas the sum of √2 and √5 is ( √2 + √5), which is an irrational number.

(ii) The difference between irrational numbers √5 and √5 is 0, which is a rational number.

(iii) The product of irrational numbers √20 and √5 is 10, which is a rational number.

(iv) The quotient of irrational numbers √20 and √5 is 2, which is a rational number.

Before attempting this online maths quiz based on the chapter number system, you must be fully prepared with all the concepts. If you want to go through the chapter again, I am providing here all the video tutorials of the chapter number system/ rational and irrational numbers for free.

Part 1:  Part 2  Part 3

Rules For The Quiz:

  • This quiz has 10 multiple-choice questions.
  • Each sum has 2 marks.
  • So the maximum marks are 20.
  • There is no time limit.
  • You should be ready with a pen and copy in your hand in order to solve the sums.
  • keep your Maths book away from you. This is the test of your memory. So do not take the help of the Maths book.
  • The correct answer and explanation are provided at the end of this quiz.

    I hope this online Maths quiz on the chapter number system has helped you to evaluate how much you are prepared with this chapter. If you have not done well in this quiz, you can have another attempt after you have prepared the chapter again.
    Do not forget to write the score you have got in this Maths quiz in the comments section below. 
    Happy learning and always say yes to Maths.

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