RS Aggarwal 2019,2020 solution class 7 chapter 1 Integers Exercise 1C

Exercise 1C

Page-12

Question 1:

Divide:

(i) 65 by −13
(ii) −84 by 12
(iii) −76 by 19
(iv) −132 by 12
(v) −150 by 25
(vi) −72 by −18
(vii) −105 by −21
(viii) −36 by −1
(ix) 0 by −31
(x) −63 by 63
(xi) −23 by −23
(xii) −8 by 1

Answer 1:

(i) 65 $÷$ (−13) = $\frac{65}{-13} =$−5

(ii) (−84) $÷$ 12 = $\frac{-84}{12} =$ −7

(iii) (−76) $÷$ 19 = $\frac{-76}{19} =$−4

(iv) (−132) $÷$ 12 = $\frac{-132}{12} =$−11

(v) (−150) $÷$ 25 = $\frac{-150}{25} =$−6

(vi) (−72) $÷$ (−18) = $\frac{-72}{-18} = 4$

(vii)  (−105) $÷$ (−21) = $\frac{-105}{-21 } =$5

(viii) (−36) $÷$ (−1) = $\frac{-36}{-1} =$36

(ix) 0 $÷$ (−31) =  $\frac{0}{-31 } =$0

(x)  (−63) $÷$ 63 = $\frac{-63}{63} =$−1

(xi)  (−23) $÷$ (−23) = $\frac{-23}{-23} =$1

(xii) (−8) $÷$ 1 =  $\frac{-8}{1} =$−8

Question 2:

Fill in the blanks

(i) 72 ÷ (......) = −4
(ii) −36 ÷ (......) = −4
(iii) (......) ÷ (−4) = 24
(iv) (......) ÷ 25 = 0
(v) (......) ÷ (−1) = 36
(vi) (......) ÷ 1 = −37
(vii) 39 ÷ (......) = −1
(viii) 1 ÷ (......) = −1
(ix) −1 ÷ (......) = −1

Answer 2:

(i)
72 ÷ (x) = −4
 $$\begin{gathered} \Rightarrow \frac{72}{x} = -4 \\ \Rightarrow x = \frac{72}{-4} = -18 \end{gathered}$$

(ii)
−36 ÷ (x) = −4
$$\begin{gathered} \Rightarrow \frac{-36}{x} = -4 \\ \Rightarrow x = \frac{-36}{-4 } = 9 \end{gathered}$$

(iii)
(x) ÷ (−4) = 24
$$\begin{gathered} \Rightarrow \frac{x}{-4} = 24 \\ \Rightarrow x = 24\times (-4) = -96 \end{gathered}$$

(iv) 
(x) ÷ 25 = 0
$$\begin{gathered} \Rightarrow \frac{x}{25} = 0 \\ \Rightarrow x = 25\times 0 = 0 \end{gathered}$$

(v)
(x) ÷ (−1) = 36
$$\begin{gathered} \Rightarrow \frac{x}{-1} = 36 \\ \Rightarrow x = 36\times (-1) = -36 \end{gathered}$$

(vi)
(x) ÷ 1 = −37
$$\begin{gathered} \Rightarrow \frac{x}{1}= -37 \\ \Rightarrow x = -37\times 1 = -37 \end{gathered}$$

(vii)
39 ÷ (x) = −1
$$\begin{gathered} \Rightarrow \frac{39}{x} = -1 \\ \Rightarrow x = -1\times 39 = -39 \end{gathered}$$

(viii) 
1 ÷ (x) = −1
$$\begin{gathered} \Rightarrow \frac{1}{x}= -1 \\ \Rightarrow x = -1\times 1 = -1 \end{gathered}$$

(ix)
−1 ÷ (x) = −1
$$\begin{gathered} \Rightarrow \frac{-1}{x} = -1 \\ \Rightarrow x = \frac{-1}{-1}= 1 \end{gathered}$$

Question 3:

Write (T) for true and (F) for false for each of the following statements.

(i) 0 ÷ (−4) = 0
(ii) (−6) ÷ 0 = 0
(iii) (−5) ÷ (−1) = −5
(iv) (−8) ÷ 1 = −8
(v) (−1) ÷ (−1) = −1
(vi) (−9) ÷ (−1) = 9

Answer 3:

(i) True (T). Dividing zero by any integer gives zero.
(ii) False (F). Division by zero gives an indefinite number.

(iii) False (F). $\frac{-5}{-1} = 5$

(iv)  True (T). $\frac{-8}{1}= -8$

(v)  False (F). $\frac{-1}{-1 }= 1$

(vi) True (T). $\frac{-9}{-1} = 9$