# Rational Numbers Class 8 Notes CBSE Maths Chapter 1 [Free PDF Download]

## Revision Notes for CBSE Class 8 Maths Chapter 1 - Free PDF Download

Students of Class 8 study hard throughout the year to score high marks in annual examinations. However, unfortunately, they fail to revise the whole concept during exam time because of the bulky syllabus. As a result, they skip some concepts which are important and though they have studied them earlier they have not revised them. Many students even don't know the concept of making notes, they simply keep on reading the whole syllabus.

Realizing all these problems, Vedantu subject experts are at your door. Vedantu Mathematics experts have designed CBSE Class 8 Maths Chapter 1 Revision Notes in such a way that all the definitions, formulas, and properties of Rational numbers are covered here.

Vedantu is a platform that provides free NCERT Solutions and other study materials for students. Students just have to download CBSE Class 8 Maths Rational Numbers Notes free PDF by clicking once on the link given below and can use it even without the internet, from anywhere. You can also download NCERT Solutions for Class 8 Maths and NCERT Solution for Class 8 Science to help you to revise the complete syllabus and score more marks in your examinations.

## Rational Numbers Class 8 Notes

Before getting to the revision notes, let us first understand the topics covered in Chapter 1 Rational Numbers.

## Topics Covered in NCERT Maths Class 8 Chapter 1 Rational Numbers

 Section No. Topic Name 1.1 Introduction to Rational Numbers 1.2 Properties of Rational Numbers 1.2.1 Closure Property 1.2.2 Commutative Property 1.2.3 Associative Property 1.2.4 The Role of Zero (0) 1.2.5 The Role of One (1) 1.2.6 Negative of a Number 1.2.7 Reciprocal of a Number 1.2.8 Distributivity of Multiplication over Addition for Rational Numbers 1.3 Representation of Rational Numbers on the Number Line 1.4 Rational Numbers between Two Rational Numbers

These all topics are discussed below in a concise way for easy and quick understanding. Introduction to rational numbers includes the topics such as what rational numbers is, how to write rational numbers in standard form and what are the types of rational numbers.

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## Access Class 8 Maths Chapter 1 – Rational Numbers Notes

1. Rational Numbers are numbers in the form of $\dfrac{p}{q}$ such that $q>0$. It is denoted by “Q”.

2. If the numerator and denominator are coprime and $q>0$ then the Rational Number is of the standard form.

3. Types of Rational Numbers:

i. Positive Rational Numbers: The sign of both the numerator and denominator are the same, i.e., either both are positive or both are negative. Ex: $\dfrac{2}{3},\dfrac{-7}{-8},...$

ii. Negative Rational Numbers: The sign of both the numerator and denominator are the same, i.e., if the numerator is negative, the denominator will be positive. Similarly, if the numerator is positive, the denominator is negative. Ex: $\dfrac{2}{-3},\dfrac{-7}{8},...$

iii. Zero Rational Numbers: The numerator is always zero. Ex: $\dfrac{0}{3},\dfrac{0}{8},...$

4. Properties of Rational Numbers:

I. Closure Property: The addition, subtraction and multiplication operations result in closure Property, i.e., for any two rational numbers in these operations, the answer is always a rational number.

ii. Commutative Property: The various order of rational numbers in the operations like addition and multiplication results in the same answer.

Ex: $\dfrac{2}{3}+\dfrac{4}{8}=\dfrac{4}{8}+\dfrac{2}{3},...$

iii. Associative Property: The grouping order does not matter in the operations like addition or multiplication, i.e., the place where we add the parenthesis does not change the answer. Ex: $\dfrac{8}{9}+\left( \dfrac{4}{5}+\dfrac{6}{7} \right)=\left( \dfrac{8}{9}+\dfrac{4}{5} \right)+\dfrac{6}{7}$

iv. Distributive Property: The rational numbers are distributed in the following way:

• $a\left( b+c \right)=ab+ac$

• $a\left( b-c \right)=ab-ac$

v. General Properties:

• A rational number can be a fraction or not, but vice versa is true.

• Rational numbers can be denoted on a number line.

• There is $'n'$ number of rational numbers between any two rational numbers.

5. Role of Zero: Also known as the Additive Identity

Whenever $'0'$ is added to any rational number, the answer is the Rational number itself.

Ex: If $'a'$ is any rational number, then $a+0=0+a=a$

6. Role of One: Also known as the Multiplicative Identity.

Whenever $'1'$ is multiplied by any rational number, the answer is the Rational number itself.

Ex: If $'a'$ is any rational number, then $a\times 1=1\times a=a$

The Additive Inverse of any rational number is the same rational number with the opposite sign. The additive inverse of $\dfrac{a}{b}$ is $-\dfrac{a}{b}$. Similarly, the additive inverse of $-\dfrac{a}{b}$ is $\dfrac{a}{b}$, where $\dfrac{a}{b}$ is the rational number.

8. Multiplicative Inverse: Also known as the Reciprocal.

The Multiplicative Inverse of any rational number is the inverse of the same rational number. The multiplicative inverse of $\dfrac{a}{b}$ is $\dfrac{b}{a}$. Similarly, the multiplicative inverse of $\dfrac{b}{a}$ is $\dfrac{a}{b}$, where $\dfrac{a}{b}$ and $\dfrac{b}{a}$ is any rational number.

## FAQs on Rational Numbers Class 8 Notes CBSE Maths Chapter 1 [Free PDF Download]

1. How Rational Numbers Class 8 Notes will be Helpful?

Rational number Class 8 notes include diagrams, solved examples, formulas, and important terms that enable you to quickly revise the chapter easily at no time. Class 8 Maths rational notes are prepared by the subject experts as per the latest exam pattern issued by the CBSE board. It includes all the additional details that students might require to prepare for school exams and other competitive exams like the Olympiad.

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