Exercise 3D
Q1 | Ex-3D | Class 7 | Rational Numbers | SChand | New Learning Composite Maths | Chapter 4 | myhelper
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Question 1
Find Each Sum
(a) 12+(7−8)
Sol :
=12−78
=4−78=−38
(b) −14+(7−12)
Sol :
=−14−712
=−3−712=−1012
=−56
(c) 435+(−7110)
Sol :
=435−7170
=86−7110=1510=32
(d) −1715+(−1930)
Sol :
=−2215−1930
=−44−1930=−6330
=−2110
Q2 | Ex-3D | Class 7 | Rational Numbers | SChand | New Learning Composite Maths | Chapter 4 | myhelper
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Question 2
Subtract:
(a) 113 from −526
Sol :
=−526−113
=−5×1−1×226
=−5−226=−726
(b) 8−15from −1130
Sol :
=−1130−(8−15)
=−1130+815
=−11×1+8×230=−11+1630
=+530=16
(c) 1425 from −3750
Sol :
=−3750−1425
=−15750−2925
=−21550=−4310
(d) −1311 from 3522
Sol :
=3522−(−1311)
=7122+1411
=9922=412
Q3 | Ex-3D | Class 7 | Rational Numbers | SChand | New Learning Composite Maths | Chapter 4 | myhelper
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Question 3
Add.
(a) 7−8 and 511
Sol :
=7−8+511=−77+4088
=−3788
(b) 123 and −215
Sol :
=53−115
=25−3315=−815
(c) −137 and 138
Sol :
=−137+138
=107+118
=−80−7756
=−356
(d) −14711 and −35910
Sol :
=−14711+(−35910)
=−16111−35910
=−5559110=−5059110
Q4 | Ex-3D | Class 7 | Rational Numbers | SChand | New Learning Composite Maths | Chapter 4 | myhelper
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Question 4
(a) 37 from 5−9
Sol :
=5−9−37
=−59−37
=−35−2763=−6263
(b) −922 from −521
Sol :
=−521−(−922)
=−521+922
=−110+189462
=79462
(c) −117 and −2310
Sol :
=−2310−(−117)
=−2310+87
=−161+8070=−8170
=−11170
(d) −658 from 1411
Sol :
=1511+538
=120+58388=70388
=78788
Q5 | Ex-3D | Class 7 | Rational Numbers | SChand | New Learning Composite Maths | Chapter 4 | myhelper
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Question 5
Find the sum.
(a) −1720+(−1925)
Sol :
=−1720−1925
=−85−76100=−161100
=−161100
(b) 158+9−12
Sol :
=158+9−12
=138−912
=39−1824=2124
(c) −256+2914
Sol :
=−176+3714
=−119+11142
=−842
=−421
Q6 | Ex-3D | Class 7 | Rational Numbers | SChand | New Learning Composite Maths | Chapter 4 | myhelper
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Question 6
Subtract:
(a) −138 from 5712
Sol :
=6712+118
=134+3324
=16724=62324
(b) −1415 from 11−20
Sol :
=11−20−(−1415)
=−1120+1915
=−33+7660=4360
(c) 4710 from 18−25
Sol :
=18−25−4710
=−825−4710
=−36−23550=−27150
=−52150
Q7 | Ex-3D | Class 7 | Rational Numbers | SChand | New Learning Composite Maths | Chapter 4 | myhelper
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Question 7
Simplify:
(a) −10+(−615)
Sol :
=−1615
(b) −1980−(−3)
Sol :
=26180
(c) 18−19+1138−2757
Sol :
=−25114
(d) −517+(−25)
Sol :
=−5985
(e) 6+9−11
Sol :
=5211
(f) −518+17−24+12936–2
Sol :
=−8572
Q8 | Ex-3D | Class 7 | Rational Numbers | SChand | New Learning Composite Maths | Chapter 4 | myhelper
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Question 8
5−9−7−12−2−(−−5−6)
Sol :
=−59+712−2+56
=−20−21−72+3036=−4136=−1536
Q9 | Ex-3D | Class 7 | Rational Numbers | SChand | New Learning Composite Maths | Chapter 4 | myhelper
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Question 9
Subtract (37+5−9) from the negative of 8−63
Sol :
8−63−(37+5−9)
=−863−(37−59)
=−863−37+59
=−8−27+3563
=0
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