Solutions For All Chapters Maths Class 8
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) 2/8
(ii) -5/9
(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 = 11/5
(ii) x = -13/17
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 6/13 by the reciprocal of -7/16.
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 8/9 the multiplicative inverse of -1 1/8? Why or Why not?
Solution:
Here -1 1/8 = -9/8.
Since multiplicative inverse of 8/9 is 9/8 but not -9/8
8/9 is not the multiplicative inverse of -1 1/8
Ex 1.1 Class 8 Maths Question 9.
If 0.3 the multiplicative inverse of 3 1/3? Why or why not?
Solution:
Multiplicative inverse of 0.3 or 3/10is 10/3.
Thus, 0.3 is the multiplicative inverse of 3 1/3.
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
[∵1/0 is not defined]
(ii) Reciprocal of 1 = 1/1= 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 1/x, 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) -1/5
(iv) x
(v) rational number
(vi) positive