Class 8 Maths Chapter 1 Rational Numbers All Exercise NCERT Solutions

Class 8 Maths Chapter 1 Rational Numbers All Exercise NCERT Solutions

• Class 8 Maths Rational Numbers Exercise 1.1
• Class 8 Maths Rational Numbers Exercise 1.2

NCERT Solutions for Class 8 Maths Chapter 1 Rational Numbers Exercise 1.1

Ex 1.1 Class 8 Maths Question 1.
Using appropriate properties find:

Solution:

Ex 1.1 Class 8 Maths Question 2.
Write the additive inverse of each of the following:
(i) 28
(ii) −59
(iii) −6−5
(iv) 2−9
(v) 19−6
Solution:

Ex 1.1 Class 8 Maths Question 3.
Verify that -(-x) = x for
(i) x = 115
(ii) x = −1317
Solution:

Ex 1.1 Class 8 Maths Question 4.
Find the multiplicative inverse of the following:

Solution:

Ex 1.1 Class 8 Maths Question 5.
Name the property under multiplication used in each of the following:

Solution:
(i) Commutative property of multiplication
(ii) Commutative property of multiplication
(iii) Multiplicative inverse property

Ex 1.1 Class 8 Maths Question 6.
Multiply 613 by the reciprocal of −716.
Solution:

Ex 1.1 Class 8 Maths Question 7.
Tell what property allows you to compute

Solution:
Since a × (b × c) = (a × b) × c shows the associative property of multiplications.

Ex 1.1 Class 8 Maths Question 8.
Is 89 the multiplicative inverse of -118? Why or Why not?
Solution:
Here -118 = −98.
Since multiplicative inverse of 89 is 98 but not −98
89 is not the multiplicative inverse of -118

Ex 1.1 Class 8 Maths Question 9.
If 0.3 the multiplicative inverse of 313? Why or why not?
Solution:

Multiplicative inverse of 0.3 or 310 is 103.
Thus, 0.3 is the multiplicative inverse of 313.

Ex 1.1 Class 8 Maths Question 10.
Write:
(i) The rational number that does not have a reciprocal.
(ii) The rational numbers that are equal to their reciprocals.
(iii) The rational number that is equal to its negative.
Solution:
(i) 0 is the rational number which does not have its reciprocal
[∵ 10 is not defined]
(ii) Reciprocal of 1 = 11 = 1
Reciprocal of -1 = 1−1 = -1
Thus, 1 and -1 are the required rational numbers.
(iii) 0 is the rational number which is equal to its negative.

Ex 1.1 Class 8 Maths Question 11.
Fill in the blanks.
(i) Zero has ……….. reciprocal.
(ii) The numbers ……….. and ……….. are their own reciprocals.
(iii) The reciprocal of -5 is ………
(iv) Reciprocal of 1x, where x ≠ 0 is ……….
(v) The product of two rational numbers is always a …………
(vi) The reciprocal of a positive rational number is ……….
Solution:
(i) no
(ii) -1 and 1
(iii) −15
(iv) x
(v) rational number
(vi) positive

Class 8 Maths Chapter 1 Rational Numbers Exercise 1.2

Ex 1.2 Class 8 Maths Question 1.
Represent these numbers on the number line
(i) 74
(ii) −56
Solution:
(i) 74

Here, point A represents 74 on the number line.
(ii) −56

Here, point B represents −56 on the number line.

Ex 1.2 Class 8 Maths Question 2.
Represent −211, −511 , −911 on a number line.
Solution:
We have −211, −511 and −911

Here, point A represents −211 , point B represents −511, point C represents −911

Ex 1.2 Class 8 Maths Question 3.
Write five rational numbers which are smaller than 2.
Solution:
Required five rational numbers smaller than 2 are
1, 0, 12, 13 and 14

Ex 1.2 Class 8 Maths Question 4.
Find ten rational numbers between −25 and 12.
Solution:

Ex 1.2 Class 8 Maths Question 5.
Find five rational numbers between
(i) 23 and 45
(ii) −32 and 53
(iii) 14 and 12
Solution:

Ex 1.2 Class 8 Maths Question 6.
Write five rational numbers greater than -2.
Solution:
Required rational numbers greater than -2 are -1, 0, 12, 34 , 1.

Ex 1.2 Class 8 Maths Question 7.
Find ten rational numbers between 35 and 34.
Solution:
Given rational numbers are 35 and 34.

NCERT Solutions for Class 8 Maths

• Chapter 1 Rational Numbers
• Chapter 2 Linear Equations in One Variable
• Chapter 3 Understanding Quadrilaterals
• Chapter 4 Practical Geometry
• Chapter 5 Data Handling
• Chapter 6 Squares and Square Roots
• Chapter 7 Cubes and Cube Roots
• Chapter 8 Comparing Quantities
• Chapter 9 Algebraic Expressions and Identities
• Chapter 10 Visualising Solid Shapes
• Chapter 11 Mensuration
• Chapter 12 Exponents and Powers
• Chapter 13 Direct and Indirect proportions
• Chapter 14 Factorisation
• Chapter 15 Introduction to Graphs
• Chapter 16 Playing with Numbers