EXERCISE 6.2
1) Using the number line write the integer which is :
(a) 3 more than 5.
Ans: Hence 3 more than 5, ⇒ 5 +3 = 8.
(b) 5 more than −5.
Ans: Hence 5 more than −5, ⇒ −5 + 5 = 0.
(c) 6 less than 2.
Ans: Hence 6 less than 2, ⇒ 2 – 6 = − 4.
(d) 3 less than −2.
Ans: Hence 3 is less than − 2. i.e. − 2 – 3 = − 5.
2) Use number line and add the following integers :
(a) 9 + (− 6) = 3.
(b) 5 + ( − 11 ) = − 6.
(c) (− 1) + (− 7 ) = −8
(d)( −5 ) + 10 = 5
(e)( − 1 ) +( −2 ) + ( −3 ) = − 6
(f)( − 2 ) + 8 + ( −4 ) = 2.
3) Add without using number line :
(a) 11 + ( −7 )
Ans.
= 11 − 7
= 4.
(b) (− 13) + (+18)
Ans.
= – 13 + 18
= 5 .
(c) (− 10) + (+ 19)
Ans.
= − 10 + 19
= 9.
(d) ( − 250 ) + ( + 150 )
Ans.
= − 250 + 150
= − 100.
(e) (− 380) + (−270)
Ans.
= (− 380) – 270
= − 650.
(f) (− 217 ) + (−100 )
Ans.
= (−217 ) − 100
= −317.
4) Find the sum of :
(a) 137 and – 354
Ans.
= 137 + (−354)
= − 217 .
(b) −52 and 52
Ans.
= (−52)+52
= 0.
(c) −312, 39 and 192
Ans.
= (−312) + 39 + 192
= − 312 + 231
= − 81.
(d) −50, −200 and 300
Ans.
= (−50) + (−200) + 300
= -50 – 200 +300
= − 250 + 300
= 50.
5) Find the value of :
(a) (−7) + (−9) + 4 + 16
Ans.
= −7 −9 + 4 + 16
= −16 + 20
= 4 .
(b) (37) + (−2) + (−65) + (−8)
Ans.
= 37 – 2 – 65 − 8
= 35 − 73
= − 38.