### Whole Numbers-Solutions Ex-2.2

CBSE Class –VI Mathematics
NCERT Solutions
Chapter 2 Whole Numbers (Ex. 2.2)

Question 1. Find the sum by suitable rearrangement:
(a) 837 + 208 + 363
(b) 1962 + 453 + 1538 + 647
Answer: (a) 837 + 208 + 363
= (837 + 363) + 208
= 1200 + 208
= 1408
(b) 1962 + 453 + 1538 + 647
= (1962 + 1538) + (453 + 647)
= 3500 + 1100
= 4600
Question 2. Find the product by suitable arrangement:
(a) 2 x 1768 x 50
(b) 4 x 166 x 25
(c) 8 x 291 x 125
(d) 625 x 279 x 16
(e) 285 x 5 x 60
(f) 125 x 40 x 8 x 25
Answer: (a) 2 x 1768 x 50
= (2 x 50) x 1768
= 100 x 1768
= 176800
(b) 4 x 166 x 25
= (4 x 25) x 166
= 100 x 166
= 16600
(c) 8 x 291 x 125
= (8 x 125) x 291
= 1000 x 291
= 291000
(d) 625 x 279 x 16
= (625 x 16) x 279
= 10000 x 279
= 2790000
(e) 285 x 5 x 60
= 285 x (5 x 60)
= 285 x 300
= 85500
(f) 125 x 40 x 8 x 25
= (125 x 8) x (40 x 25)
= 1000 x 1000
= 1000000
Question 3. Find the value of the following:
(a) 297 x 17 + 297 x 3
(b) 54279 x 92 + 8 x 54279
(c) 81265 x 169 – 81265 x 69
(d) 3845 x 5 x 782 + 769 x 25 x 218
Answer: (a) 297 x 17 + 297 x 3
= 297 x (17 + 3)
= 297 x 20
= 5940
(b) 54279 x 92 + 8 x 54279
= 54279 x (92 + 8)
= 54279 x 100
= 5427900
(c) 81265 x 169 – 81265 x 69
= 81265 x (169 – 69)
= 81265 x 100
= 8126500
(d) 3845 x 5 x 782 + 769 x 25 x 218
= 3845 x 5 x 782 + 769 x 5 x 5 x 218
= 3845 x 5 x 782 + 3845 x 5 x 218
= 3845 x 5 x (782 + 218)
= 3845 x 5 x 1000
= 19225000
Question 4. Find the product using suitable properties:
(a) 738 x 103
(b) 854 x 102
(c) 258 x 1008
(d) 1005 x 168
= 738 x (100 + 3)
= 738 x 100 + 738 x 3
= 73800 + 2214
= 76014
(b) 854 x 102
= 854 x (100 + 2)
= 854 x 100 + 854 x 2
= 85400 + 1708
= 87108
(c) 258 x 1008
= 258 x (1000 + 8)
= 258 x 1000 + 258 x 8
= 258000 + 2064
= 260064
(d) 1005 x 168
= (1000 + 5) x 168
= 1000 x 168 + 5 x 168
= 168000 + 840
= 168840
Question 5. A taxi-driver, filled his car petrol tank with 40 litres of petrol on Monday. The next day, he filled the tank with 50 litres of petrol. If the petrol costs Rs.44 per litre, how much did he spend in all on petrol?
Answer: Quantity of Petrol filled on Monday = 40 litres
Quantity of Petrol filled on next day = 50 litres
Total Quantity of petrol filled = 90 litres
Now, Cost of 1 litre petrol = Rs.44
Cost of 90 litres of petrol = 44 x 90
= 44 x (100 – 10)
= 44 x 100 – 44 x 10
= 4400 – 440
= Rs.3960
Therefore, he spent Rs.3960 on petrol.
Question 6. A vendor supplies 32 litres of milk to a hotel in the morning and 68 litres of milk in the evening. If the milk costs Rs.15 per litre, how much money is due to the vendor per day?
Answer: Quantity of milk supplied in the morning = 32 litres
Quantity of milk supplied in the evening = 68 litres
Total supply = 32 + 68 = 100 litres
Now Cost of 1 litre milk = Rs.15
Cost of 100 litres milk = 15 x 100 = Rs.1500
Therefore, Rs.1500 is due to the vendor per day.
Question 7. Match the following:
(i)425 x 136 = 425 x (6 + 30 + 100) (a) Commutativity under multiplication
(ii) 2 x 49 x 50 = 2 x 50 x 49 (b) Commutativity under addition
(iii) 80 + 2005 + 20 = 80 + 20 + 2005 (c) Distributivity of multiplication over addition
Answer: (i) 425 x 136 = 425 x (6 + 30 + 100) (c) Distributivity of multiplication over addition
(ii) 2 x 49 x 50 = 2 x 50 x 49 (a) Commutativity under multiplication
(iii) 80 + 2005 + 20 = 80 + 20 + 2005 (b) Commutativity under addition.