Integers Ex-1.2

NCERT solutions for Class 7 Integers Maths 

NCERT Solutions for Class 7 Maths Integers

Class –VII Mathematics (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 $– 7$: $– 5 + \left( { – 2} \right) = – 7$

(b) One such pair whose difference is $– 10$: $– 2 – 8 = – 10$

(c) One such pair whose sum is 0: $– 5 + 5 = 0$

NCERT Solutions for Class 7 Maths Exercise 1.2

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) $– 2 – \left( { – 10} \right) – 2 + 10 = 8$

(b) $\left( { – 7} \right) + 2 = – 5$

(c) $\left( { – 2} \right) – 1 = – 2 – 1 = – 3$

NCERT Solutions for Class 7 Maths Exercise 1.2

Question 3.In a quiz, team A scored $– 40,10,0$ and team B scores 10, 0, $– 40$ 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 $10,0, – 40$

Total score of Team B = $10 + 0 + \left( { – 40} \right) = 10 + 0 – 40 = – 30$

Thus, scores of both teams are same.

Yes, we can add integers in any order due to commutative property.

NCERT Solutions for Class 7 Maths Exercise 1.2

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) $\left( { – 5} \right) + \left( { – 8} \right) = \left( { – 8} \right) + \underline {\left( { – 5} \right)}$ [Commutative property]

(ii) $– 53 + \underline 0 = – 53$ [Zero additive property]

(iii) $17 + \underline {\left( { – 17} \right)} = 0$ (Additive identity]

(iv)$\left[ {13 + \left( {12} \right)} \right] + \underline {\left( { – 7} \right)} = 13 + \left[ {\left( { – 12} \right) + \left( { – 7} \right)} \right]$ [Associative property]

$\left( { – 4} \right) + \left[ {15 + \left( { – 3} \right)} \right] = \left[ { – 4 + 15} \right] + \underline {\left( { – 3} \right)}$ [Associative property]