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NCERT Solutions for Class 8 maths Chapter 1 : rational Numbers Exercise 1.1





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 and comment at the end of the page.
Question 1:  
Using appropriate properties find:
NCERT Solutions for Class 8 maths Chapter 1 : rational Numbers

Answer
  1. Using commutativity property of rational number Ncert Solutions for rational Numbers Class 8 Exercise 1.1
    Now using Distributivity property
    Ncert Solutions for rational Numbers Class 8 Exercise 1.1
    Ncert Solutions for rational Numbers Class 8 Exercise 1.1
    (ii) Using commutativity property of rational numbers
    Ncert Solutions for rational Numbers Class 8 Exercise 1.1
       Now using Distributivity property
    Ncert Solutions for rational Numbers Class 8 Exercise 1.1
Question 2    
Write the additive inverse of each of the following:
  1. 2/8
  2. -5/9
  3. -6/-5
  4.  2/-9
  5. 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:
  1.  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.
  1. -13
  2. -13/19
  3.  1/5
  4. -5/8 X -3/7
  5. -1 X -2/5
  6.  - 1

Answer
  1. -13 Multiplicative inverse =-1/13
  2. -13/19 Multiplicative inverse =-19/13
  3. 1/5 Multiplicative inverse =5
  4. -5/8 X -3/7 =15/56 Multiplicative inverse =56/15
  5. -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:
NCERT Solutions for Class 8 maths Chapter 1 : rational Numbers
Answer:
  1. 1 is the multiplicative identity
  2. Commutatively
  3. 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
NCERT Solutions for Class 8 maths Chapter 1 : rational Numbers
Answer:
Associativity


Question 8  
Is   8/9 the multiplicative inverse of NCERT Solutions for Class 8 maths Chapter 1 : rational Numbers
Why or why not?
Answer:
NCERT Solutions for Class 8 maths Chapter 1 : rational Numbers
=-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
NCERT Solutions for Class 8 maths Chapter 1 : rational Numbers
 Why or why not?

Answer:
NCERT Solutions for Class 8 maths Chapter 1 : rational Numbers
=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:
  1. 0
  2. 1 and -1
  3. 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:
  1. No
  2. 1 and -1
  3.  -1/5
  4. X
  5. Rational Number
  6. Positive rational number

Download Rational numbers Class8 Exercise 1.1 as pdf
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Class 8 Maths Class 8 Science
Reference Books for class 8 Math

Given below are the links of some of the reference books for class 8 Math.

  1. Mathematics Foundation Course for JEE/Olympiad : Class 8 This book can take students maths skills further. Only buy if child is interested in Olympiad/JEE foundation courses.
  2. Mathematics for Class 8 by R S Aggarwal Detailed Mathematics book to clear basics and concepts. I would say it is a must have book for class 8 student.
  3. Pearson Foundation Series (IIT -JEE / NEET) Physics, Chemistry, Maths & Biology for Class 8 (Main Books) | PCMB Combo : These set of books could help your child if he aims to get extra knowledge of science and maths. These would be helpful if child wants to prepare for competitive exams like JEE/NEET. Only buy if you can provide help to the child while studying.
  4. Reasoning Olympiad Workbook - Class 8 :- Reasoning helps sharpen the mind of child. I would recommend students practicing reasoning even though they are not appearing for Olympiad.

You can use above books for extra knowledge and practicing different questions.







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