Integers
Exercise 6.3
1). Find
(a) 35 – (20) (b) 72 – (90)
(c) (– 15) – (– 18) (d) (–20) – (13)
(e) 23 – (– 12) (f) (–32) – (– 40)
Answer:
(a) 35 – (20)
35 – (20) = 35 – 20
= 15
(b) 72 – (90)
72 – (90) = 72 – 90
= – 18
(c) (– 15) – (– 18)
-15 – (- 18) = – 15 – (- 18)
= – 15 + 18
= 3
(d) (–20) – (13)
(–20) – (13) = (–20) – (13)
= – 20 – 13
= – 33
(e) 23 – (– 12)
23 – (- 12) = 23 – (-12)
= 23 + 12
= 35
(f) (–32) – (– 40)
(–32) – (– 40) = (–32) – (– 40)
= – 32 + 40
= 8
2). Fill in the blanks with >, < or = sign.
(a) (– 3) + (– 6) ______ (– 3) – (– 6)
(b) (– 21) – (– 10) _____ (– 31) + (– 11)
(c) 45 – (– 11) ______ 57 + (– 4)
(d) (– 25) – (– 42) _____ (– 42) – (– 25)
Answer:
(a). – 3) + (– 6) ______ (– 3) – (– 6)
L.H.S = (-3) + (-6)
= -3 – 6 = -9
R.H.S = (-3) – (-6)
= -3 + 6 = 3
(– 3) + (– 6) < (– 3) – (– 6)
(b). (– 21) – (– 10) _____ (– 31) + (– 11)
L.H.S = (-21) – (-10)
= -21+ 10 = -11
R.H.S = (-31) + (-11)
= -31 – 11 = -42
(– 21) – (– 10) > (– 31) + (– 11)
(c). 45 – (– 11) ______ 57 + (– 4)
L.H.S = 45 – (-11)
= 45 + 11 = 56
R.H.S = 57 + (-4)
= -57 – 4 = 53
45 – (– 11) > 57 + (– 4)
(d). (– 25) – (– 42) _____ (– 42) – (– 25)
L.H.S = (-25) – (-42)
= -25 + 42 = 17
R.H.S = (-42) – (-25)
= -42 + 25 = -17
(– 25) – (– 42) > (– 42) – (– 25)
3). Fill in the blanks.
(a) (– 8) + _____ = 0
(b) 13 + _____ = 0
(c) 12 + (– 12) = ____
(d) (– 4) + ____ = – 12
(e) ____ – 15 = – 10
Answer:
(a) (– 8) + 8 = 0
(b) 13 + (-13) = 0
(c) 12 + (– 12) = 0
(d) (– 4) + (-8) = – 12
(e) 5 – 15 = – 10
4). Find
(a) (– 7) – 8 – (– 25)
(– 7) – 8 – (– 25) = (– 7) – 8 – (– 25)
= – 7 – 8 + 25
= -15 + 25
= 10
(b) (– 13) + 32 – 8 – 1
(– 13) + 32 – 8 – 1 = (– 13) + 32 – 8 – 1
= – 13 + 32 – 8 – 1
= 19 – 8 – 1
= 11 – 1
= 10
(c) (– 7) + (– 8) + (– 90)
(– 7) + (– 8) + (– 90) = (– 7) + (– 8) + (– 90)
= -7 – 8 – 90
= – 15 – 90
= – 105
(d) 50 – (– 40) – (– 2)
50 – (– 40) – (– 2) = 50 – (– 40) – (– 2)
= 50 + 40 + 2
= 90 + 2
= 92.
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