Rs Aggarwal Solutions: Exercise 1E - Rational Numbers | Mathematics (Maths) Class 8 PDF Download

Q.1. Simplify:
(i)
(ii)
(iii)
(iv)
(v)
(vi)
Ans.
(i)

(ii)

(iii)


(iv)

(v)

(vi)


Q.2. Verify whether the given statement is true or false:
(i)
(ii)
(iii)
(iv)
Ans.
(i)


(ii)

(iii)

(iv)


Q.3. Verify whether the given statement is true or false:
(i)
(ii)
(iii)
Ans.
(i)



(ii)




(iii)




Q.4. The product of two rational numbers is −9. If one of the numbers is −12, find the other.
Ans.
Let the number be x.
Now,


Q.5. The product of two rational numbers is If one of the numbers is

find the other.
Ans.
Let the number be x.
Now,


Q.6. By what rational number should we multiply
Ans.
Let the number be x.
Now,



Q.7. By what rational number should be multiplied to obtain

Ans.
Let the number be x.
Now,



Q.8. By what number should be divided to get

Ans.
Let the number be x.
Now,



Q.9. Divide the sum of by the product of 

Ans.


Q.10. Divide the sum of by their difference.
Ans.
 

Q.11. Fill in the blanks:
(i)
(ii)
(iii)
(iv)
Ans.
(i)


(ii)

(iii)

(iv)


Q.12. 
(i) Are rational numbers always closed under division?
(ii) Are rational numbers always commutative under division?
(iii) Are rational numbers always associative under division?
(iv) Can we divide 1 by 0?
Ans.
(i) No, rational numbers are not closed under division in general.
  it is not a rational number.
(ii) No

Therefore, division is not commutative.
(iii) No, rational numbers are not associative under division.

(iv) No, we cannot divide 1 by 0. The answer will be∞, which is not defined.