SChand Smart Mathematics Class 7 Chapter 1 Integers Exercise 1.1

 Exercise 1.1

Question 1

Find in the blanks :

(a) 1+(-1)+(-1)+1+1+(-1)

Sol :

=1-1-1+1+1-1=3-3=0

(b) (-60)+(-11)+(-9)+100

Sol :

=-60-11-9+100

=100-80=20

(c) The additive inverse of (3-8)-(-4) is

Sol :

=-5+4=-1  ∵additive inverse=+1

(d) The sum of an integer and its additive inverse is always zero

Question 2

Compare the following integers using > , < or =

(a) 7 __  -6

Sol :  >

(b) -2 __ 0

Sol : <

(c) |-8-3| __ -4

Sol :

|-8-3| __ -4

|-11| __ -4

11 > -4

(d) -19 __ |-20-1|

Sol :

-19 __ |-21|

-19 > 21

Question 3

Arrange the following integers in ascending order.

(a) -8,7,-5,13,0,4

Sol :

= -8,-5,0,4,7,13

(b) -13 , 25 , 7 , 15 , 1 , -7

Sol :

= -13 , -7 , 1 , 7, 15 , 25

Question 4

(a) -15-(-40)

Sol :

-15+40=25

(b) 136+(-127)

Sol :

=136-127=9

(c) 19-(-5)+17+0

Sol :

=36+5=41

(e) (-50)+(-150)+200

Sol :

=-50-150+200

=-200+200=0

Question 5

Verify a-(-b)=a+b far the following values of a and b

(a) a=3 , b=-5

⇒3-(-(-5))=3-(5)

=3-5=-2

a+b=3+(-5)=3-5=-2

(b) a=18 , b=25

a-(-b)=18-(-25)

=18+25=43

a+b=18+25=43

Question 6

Subtract the sum of -110 and 235 from the sum of 103 and -117

Sol :

-110+235=125

103+(-117)=103-117=-14

-14-125=-139

Question 7

Write True (T) or false (F)

(a) Additive inverse of a positive integer is always negative. (T)

(b) The sum of two integers is always positive. (F)

(c) 0 is a positive integer. (F)

(d) The sum of four different integers can never be zero. (F)

(e) -1 is the greatest negative integers. (T)

Question 8

Two cyclists start from the same point on a mountain. One travels 1200 m downward the mountain in 20 minutes, and the other travels 350 m upward the mountain in the same time. How far they from each other after 20 minutes?

Sol :

=1200+350=1550 m

Question 9

The sum of two integers is -51. If one of the integers is 14, find the other integer.

Sol :

Let the other integer =x

∵x+14=-51

x=-51-14=-65

Question 10