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In this page we have NCERT Solutions for Class 8 maths Chapter 1 : rational Numbers for
Exercise 1.1. Hope you like them and do not forget to like , social share
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Question 1:
Using appropriate properties find:
Answer
- Using commutativity property of rational number
Now using Distributivity property
(ii) Using commutativity property of rational numbers
Now using Distributivity property
Question 2
Write the additive inverse of each of the following:
- 2/8
- -5/9
- -6/-5
- 2/-9
- 19/-6
Answer:
(i) 2/8
Additive inverse = -2/8
(ii) -5/9
Additive inverse = 5/9
(iii) -6/-5 =6/5
Additive inverse = -6/5
(iv) 2/-9=-2/9
Additive inverse =2/9
(v) 19/-6= -19/6
Additive inverse =19/6
Question 3
Verify that - ( -
x) =
x for.
(i) x =11/15 (ii) x=-13/17
Answer:
- x=11/15
Additive inverse
-x=-11/15
As (11/15) + (-11/15) =0
The above also represent that additive inverse of (-11/15) is (11/15) or we can say that
- (-11/15)=11/15
Or x=-(-x)
x=-13/17
Additive inverse
-x=-13/17
As (-13/17) + (13/17) =0
The above also represent that additive inverse of (13/17) is (-13/17)) or we can say that
- (13/17) = -13/17
Or x=-(-x)
Question 4
Find the multiplicative inverse of the following.
- -13
- -13/19
- 1/5
- -5/8 X -3/7
- -1 X -2/5
- - 1
Answer
- -13
Multiplicative inverse =-1/13
- -13/19
Multiplicative inverse =-19/13
- 1/5
Multiplicative inverse =5
- -5/8 X -3/7 =15/56
Multiplicative inverse =56/15
- -1 X -2/5 =2/5
Multiplicative inverse =5/2
-1
Multiplicative inverse =-1
Question 5 :
Name the property under multiplication used in each of the following:
Answer:
- 1 is the multiplicative identity
- Commutatively
- Multiplicative inverse
Question 6:
Multiply 6/13 by the reciprocal of -7/16
Answer
Reciprocal of -7/16= -16/7
So (6/13) X ( -16/7) =-96/91
Question 7
Tell what property allows you to compute
Answer:
Associativity
Question 8
Is 8/9 the multiplicative inverse of
Why or why not?
Answer:
=-9/8
Now
(8/9) X (-9/8) = -1
So it is not the multiplicative inverse
Question 9
Is 0.3 the multiplicative inverse of
Why or why not?
Answer:
=10/3
Now
(3/10) X (10/3) =1
So it is the multiplicative inverse
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.
Answer:
- 0
- 1 and -1
- 0
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 is x ≠ 0 __________.
(v) The product of two rational numbers is always a __________.
(vi) The reciprocal of a positive rational number is __________.
Answer:
- No
- 1 and -1
- -1/5
- X
- Rational Number
- Positive rational number
Download Rational numbers Class8 Exercise 1.1 as pdf
Class 8 Maths
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