Integers
Exercise 6.2
1). Using the number line write the integer which is:
(a) 3 more than 5
Ans: 8.
(b) 5 more than –5
Ans: 0.
(c) 6 less than 2
Ans: -4.
(d) 3 less than –2
Ans: -5.
2). Use number line and add the following integers:
(a) 9 + (– 6)
Ans: 9 + (– 6) = 3
(b) 5 + (– 11)
Ans: 5 + (– 11) = -6.
(c) (– 1) + (– 7)
Ans: (– 1) + (– 7) = -8.
(d) (– 5) + 10
Ans: (– 5) + 10 = 5.
(e) (– 1) + (– 2) + (– 3)
Ans: (– 1) + (– 2) + (– 3) = -6.
(f) (– 2) + 8 + (– 4)
Ans: (– 2) + 8 + (– 4) = 2.
3). Add without using a number line:
(a) 11 + (– 7) (b) (– 13) + (+ 18)
Answer:
a). 11 + (– 7)
11 + (– 7) = 11 – 7
= 4
(b) (– 13) + (+ 18)
(– 13) + (+ 18) = -13 + 18
= 5
(c) (– 10) + (+ 19)
(– 10) + (+ 19)= -10 + 19
= 9
(d) (– 250) + (+ 150)
(– 250) + (+ 150) = -250 + 150
= -100
(e) (– 380) + (– 270)
(– 380) + (– 270) = -380 -270
= -650
(f) (– 217) + (– 100)
(– 217) + (– 100) = -217 – 100
= – 317
4). Find the sum of:
(a) 137 and – 354 (b) – 52 and 52
(c) – 312, 39 and 192 (d) – 50, – 200 and 300
Answer:
(a) 137 and – 354
137 + (-354) = 137- 354
= -217
(b) – 52 and 52
-52 + 52 = 0
(c) – 312, 39 and 192
-312 + 39 + 192 = – 312 + 39 + 192
= – 273 + 192
= -81
(d) – 50, – 200 and 300
-50 + (-200) + 300 = -50- 200 + 300
= -250 + 300
= 50
5). Find the sum:
(a) (– 7) + (– 9) + 4 + 16
(b) (37) + (– 2) + (– 65) + (– 8)
Answer:
(a) (– 7) + (– 9) + 4 + 16
(– 7) + (– 9) + 4 + 16 = (– 7) + (– 9) + 4 + 16
= – 7 – 9 + 4 + 16
= – 16 + 4 + 16
= – 12 + 16
= 4
(b) (37) + (– 2) + (– 65) + (– 8)
(37) + (– 2) + (– 65) + (– 8) = (37) + (– 2) + (– 65) + (– 8)
= 37 – 2 – 65 – 8
= 35 – 65 – 8
= – 30 – 8
= -38
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