Class 6 Maths NCERT Solutions for Chapter 6 Integers Ex – 6.3

Integers

Question 1.
Find:

(a) 35-(20)
(b) 72 (90)
(c) (-15) – (-18)
(d) (-20) – (13)
(e) 23 (-12)
(f) (-32) – (-40)

Solution:
(a)
 35 – 20 = (15 + 20) – 20
= 15 + (20 – 20) = 15 + 0 = 15
(b) 72 – 90 = 72 – (72 + 18)
= (72 – 72) + (-18)
= 0 + (-18) = -18 1
(c) (-15) – (-18) = (-15) + (additive inverse -18)
= -15 + 18 = -15 +(15 + 3)
= (-15 + 15) 43 = 0 + 3 = +3
(d) (-20) -13 = -20 -13 = -(20 + 13) = -33
(e) 23 – (-12) = 23 + 12 = 35
(f) (-32) – (-40) = -32 + 40 = (-32 + 32) +8
= 0 + 8 + 8

Question 2.
Fill in the blanks with >, < or = sign:

(a) (-3) + (-6) …… (-3) -(-6)
(b) (-21) – (-10) …… (-31) + (-11)
(e) 45 – (-11) ……. 57 + (-4)
(d) (-25) – (-42) …….. (-42) – (-25)

Solution:
(a)
 Here, (-3) + (-6) = -3 – 6 = =9
and (-3)-(-6) = -3 + 6 =3
As -9 < 3
∴ (-3) + (-6) < (-3) – (-6) (b)

(b) Here, (-21) – (-10) = -21 +10 = -11
and (-31)+ (-11) = -31 -11 = -42
As -11 > -42
∴ (-21) – (-10) > (-31) + (-11)

(c) Here, 45 – (-11) = 45 + 11 = 56
and 57 + (-4) = 57-4 = 53
As 56 > 53
∴ 45 – (-11) > 57 + (-4)

(d) Here, -25 – (-42) = -25 + 42
= -25 + (25 + 17)
= (-25 + 25) +17 = 0 + 17 = 17
and, (-42) – (-25) = -42 + 25
= (-17 – 25) + 25
= -17 + (-25 + 25) = -17 + 0 = -17
As 17 > -17
∴ (-25) – (-42) > (-42) – (-25)

Question 3.
Fill in the blanks:

(a) (-8)+ ….. = 0
(b) 13 + …….. = 0
(c) 12 + (-12) = ……
(d) (-4) + ……. = -12
(e) ………. -15 = -10

Solution:
(a)
 (-8) + (+8) = 0
(b) 13 + (-13) = 0
(c) 12 + (-12) = 0
(d) (-4) +(-8) = -12 [∵ -12 – (-4) = -12 + 4 = -8]
(e) 5-15 = -10 [∵ -10 + 15 = 5]

Question 4.
Find:

(a) (-7) – 8- (-25)
(b) (-13) + 32 – 8 – 1
(c) (-7) + (-8) + (-90)
(d) 50 – (-40) – (-2)

Solution:
(a)
 (-7) – 8 – (-25) = -7 – 8 + 25
= -15 + 25 = 10.
(b) (-13) + 32 – 8-1 = -13 – 8 – 1 + 32
= -22 + 32 = 10
(c) (-7) + (-8) + (-90) = -7 – 8 – 90 = -105.
(d) 50 – (-40) – (-2) = 50+ 40 + 2 = 92.

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