# Full Circle Manjeet Singh Mathematics Full Marks Pvt Ltd Class 7 Solution Chapter 1 Integers Exercise 1.3

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### Exercise 1.3

#### Question 1

Fill in the blanks:

(i) For any two positive integers a and b, a × (—b) = (—a) × b = ___

(ii) For any two positive integers a and b , (-a) × (-b) = ___

(iii) Product of three negative integers is a ___ integer

(iv) Product of four negative integers is a __ integer

(v) If we multiply 4 positive integers and 3 negative integers , the sign of the product is ___

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#### Question 2

(i) a × b is an integer , foe all integers a and b

(ii) For any two integers a  and b , a × b ≠ b × a

(iii) For any three integers a , b and c , (a×b)×c = a×(b×c)

(iv) For any three integers a , b and c , a×(b+c) = a×b + a×c

(v) For any integer a, a×1 = a ; 1 is the multiplicative identity for integers .

(vi) For any integer a , a×0=0×a =

#### Question 3

Find each of the following products:

(i) -5×16

(ii) 24×(-3)

(iii) 135×0

(iv) (-3)×(-3)×(-3)

(v) (-5)×(-19)×0

(vi) (-4)×(-7)×(-5)×10

#### Question 4

Take a =5 , b = -3 and c = 4  , verify that

(i) -5×16

(ii) 24×(-3)

(iii) 135×0

(iv) a×(b+c) = a×b + a×c

(v) a×(b-c) = a×b – a×c

#### Question 5

(i) Find the integer which when multiplied by —1 gives 99

(ii) Find the product using suitable property:

165 × (-67) + (-165) × 33

(iii) Find the product using suitable property:

35 + (-35)×(-99)

#### Question 6

Every f‌loor of a 20 storey building is 4 m high . A lift moves 2 m per second. How long will it take to move from 4th floor to 14th f‌loor?

Sol :

#### Question 7

The temperature of a city was 28°C on Tuesday. The temperature rose by 15°C on everyday upto Friday and fell by 2.5° C on Saturday . What was the temperature of the city on Saturday?

Sol :

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