Class 8 NCERT (CBSE) Mathematics Solutions | Chapter 1, Rational Numbers (Exercise 1.1)

 

Class VIII, CBSE Mathematics
Chapter 1, Rational Numbers (NCERT Math Solutions)  
Exercise 1.1 Solutions (Rational Numbers)
Q.1: Using appropriate properties find:
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Ans:

(i) Method - 1
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Method - 2

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(ii) Method - 1

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Method - 2

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Q.2: Write the additive inverse of each of the following:
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Ans:
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Q.3: Verify that −(−x) = x for.
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Ans: 
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Q.4: Find the multiplicative inverse of the following.
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Ans:
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Q.5: Name the property under multiplication used in each of the following:
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Ans:
(i) 1 is the multiplicative identity.
(ii) Commutativity
(iii) Multiplicative inverse
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Q.7: Tell what property allows you to compute.
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Ans:
No, for multiplicative inverse, the product will be 1. But, here the product is not 1.
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Since the product is 1 so, the answer is yes.

Q.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.
Ans:
 (i) Zero has no reciprocal.
(ii) The reciprocals of 1 is 1. Therefore, 1 is the rational number which is equal to its reciprocal.
(iii) Zero is the rational number that is equal to its negative.
Q.11: Fill in the blanks.
(i) Zero has __________ reciprocal.
Ans: no
(ii) The numbers __________ and __________ are their own reciprocals
Ans: 1, -1
(iii) The reciprocal of − 5 is __________.
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Ans: x
(v) The product of two rational numbers is always a __________.
Ans: rational number
(vi) The reciprocal of a positive rational number is __________.
Ans: positive rational number.

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