### Integers - Solutions 2

CBSE Class –VII Mathematics
NCERT Solutions
Chapter 1 Integers
(Ex. 1.2)

Question 1. Write down a pair of integers whose:
(a) sum is -7     (b) difference is -10     (c) sum is 0
Answer: (a) One such pair whose sum is -7 : ( -5, -2) (-10, 3)
(b) One such pair whose difference is -10:  (-2, 8 ), (-11, -1)
(c) One such pair whose sum is 0: (5,5) ,(6,6)
Question 2. (a) Write a pair of negative integers whose difference gives 8.
(b) Write a negative integer and a positive integer whose is  -5.
(c) Write a negative integer and a positive integer whose difference is -3.
Answer: (a) (-2, -10) (-5, -13)
(b) ( -7, 2), ( -9,4)
(c) ( -1, 2), ( -2, 1)
Question 3. In a quiz, team A scored -40,10, 0 and team B scores 0, 10, -40 in three successive rounds. Which team scored more? Can we say that we can add integers in any order?
Answer: Team A scored -40,10, 0
Total score of Team A = -40+10+0 = -30
Team B scored 0, 10, -40
Total score of Team B = 0+10 +(-40) =  0+10 - 40 =  -30
Thus, scores of both teams are same.
Yes, we can add integers in any order due to commutative property.
Question 4. Fill in the blanks to make the following statements true:
(i)$\left(-5\right)+\left(-8\right)=\left(-8\right)+\left(.......\right)$
(ii)$-53+.......=-53$
(iii)17 + ……. = 0
(iv)$\left[13+\left(-12\right)\right]+\left(.......\right)=13+\left[\left(-12\right)+\left(-7\right)\right]$
(v)$\left(-4\right)+\left[15+\left(-3\right)\right]=\left[-4+15\right]+.......$
Answer: (i) $\left(-5\right)+\left(-8\right)=\left(-8\right)+\underset{_}{\left(-5\right)}$ [Commutative property]
(ii) $-53+\underset{_}{0}=-53$ [Zero additive property]
(iii) $17+\underset{_}{\left(-17\right)}=0$ (Additive identity]
(iv)$\left[13+\left(12\right)\right]+\underset{_}{\left(-7\right)}=13+\left[\left(-12\right)+\left(-7\right)\right]$ [Associative property]
$\left(-4\right)+\left[15+\left(-3\right)\right]=\left[-4+15\right]+\underset{_}{\left(-3\right)}$ [Associative property]