In this page we have NCERT Solutions for Class 8 maths Chapter 1 Rational Numbers for Exercise 1.1. This Exercise has questions on Properties of Rational nnumber, Additive inverse, Multiplicative inverse, additive identity. Hope you like them and do not forget to like , social share
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NCERT Solutions for Class 8 maths Chapter 1 Exercise 1.1
Question 1:
Using appropriate properties find:
Answer
(i)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:
(a) $\frac {2}{8}$
(b) $ \frac {-5}{9}$
(c) $\frac {-6}{-5}$
(d) $\frac {2}{-9}$
(e) $\frac {19}{-6}$
Answer:
(i) $\frac {2}{8}$
Additive inverse of $\frac {2}{8}$= $\frac {-2}{8}$
(ii) $ \frac {-5}{9}$
Additive inverse of $ \frac {-5}{9}$ = $ \frac {5}{9}$
(iii) $\frac {-6}{-5} =\frac {6}{5}$
Additive inverse of $\frac {-6}{-5}$= $\frac {-6}{5}$
(iv)$\frac {2}{-9}=\frac {-2}{9}$
Additive inverse of $\frac {2}{-9}$ =$\frac {2}{9}$
(v) $\frac {19}{-6}= \frac {-19}{6}$
Additive inverse of $\frac {19}{-6}$ =$\frac {19}{6}$
Question 3
Verify that - ( -
x) =
x for.
(i) x =11/15 (ii) x=-13/17
Answer:
(i) 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)
(ii)
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.
(a)$-13$
(b)$ \frac {-13}{19}$
(c) $\frac {1}{5}$
(d) $\frac {-5}{8} \times \frac {-3}{7}$
(e) $-1 \times \frac {-2}{5}$
(f) $-1$
Answer
(a) $-13$
Multiplicative inverse of $-13$=$\frac {-1}{13}$
(b)$ \frac {-13}{19}$
Multiplicative inverse of $ \frac {-13}{19}$ =$ \frac {-19}{13}$
(c)$\frac {1}{5}$
Multiplicative inverse of $\frac {1}{5}$=$5$
(d) $\frac {-5}{8} \times \frac {-3}{7}=\frac {15}{56}$
Multiplicative inverse of $\frac {-5}{8} \times \frac {-3}{7}$ =$\frac {56}{15}$
(e) $-1 \times \frac {-2}{5}= \frac {2}{5}$
Multiplicative inverse of $-1 \times \frac {-2}{5}$ =$ \frac {5}{2}$
(f) $-1$<
Multiplicative inverse of $-1$=-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 $ \frac {6}{13} \times (- \frac {16}{7}) =- \frac {96}{91}$
Question 7
Tell what property allows you to compute
Answer:
Associativity
Question 8
Is 8/9 the multiplicative inverse of $-1 \frac {1}{8}$
Why or why not?
Answer:
$-1 \frac {1}{8}$
$=\frac {-9}{8}$
Now
$ \frac {8}{9} \times (-\frac {9}{8}) = -1$
So it is not the multiplicative inverse
Question 9
Is 0.3 the multiplicative inverse of $3 \frac {1}{3}$
Why or why not?
Answer:
$3 \frac {1}{3}$
=10/3
Now
$ \frac {3}{10} \times \frac {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
Summary
- NCERT Solutions for Class 8 maths Chapter 1 Rational Numbers Exercise 1.1 has been prepared by Expert with utmost care. If you find any mistake.Please do provide feedback on mail. You can download the solutions as PDF in the below Link also
Download Rational numbers Class8 Exercise 1.1 as pdf
- This chapter 1 has total 2 Exercise 1.1 and 1.2. This is the first exercise in the chapter.You can explore previous exercise of this chapter by clicking the link below
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