1.Find:
(i) 0.2 × 6
Solution:
First, we multiply 2 × 6 = 12
Now, put the decimal point from 1 digit right because we have decimal point from one digit in 0.2
Hence, 0.2 × 6 = 1.2
(ii) 8 × 4.6
Solution:
First, we multiply 8 × 46 = 368
Now, put the decimal point from 1 digit right because we have decimal point from one digit in 4.6
Hence, 8 × 4.6 = 36.8
(iii) 2.71 × 5
Solution:
First, we multiply 271 × 5 = 1355
Now, put the decimal point from 2 digits right because we have decimal point from two digit in 2.71
Hence, 2.71 × 5 = 13.55
(iv) 20.1 × 4
Solution:
First, we multiply 201 × 4 = 804
Now, put the decimal point from 1 digit right because we have decimal point from one digit in 20.1
Hence, 20.1 × 4 = 80.4
(v) 0.05 × 7
Solution:
First, we multiply 5 × 7 = 35
Now, put the decimal point from 2 digits right because we have decimal point from two-digit in 0.05
Hence, 0.05 × 7 = 0.35
(vi) 211.02 × 4
Solution:
First, we multiply 21102 × 4 = 84408
Now, put the decimal point from 2 digits right because we have decimal point from two-digit in 211.02
Hence, 211.02 × 4 = 844.08
(vii) 2 × 0.86
Solution:
First, we multiply 2 × 86 = 172
Now, put the decimal point from 2 digits right because we have decimal point from two-digit in 0.86
Hence, 2 × 0.86 = 1.72
2. Find the area of rectangle whose length is 5.7cm and breadth is 3 cm.
Solution:
Given,
Length = 5.7 cm
breadth = 3 cm
Now,
Area of rectangle = length × breadth
= 5.7 cm × 3 cm
= 17.1 cm2
Hence, requird area is 17.1 cm2
3. Find:
(i) 1.3 × 10
Solution:
When we multiply a decimal by 10, the point of decimal is shifted to the right by one place.
Thus,
1.3 × 10 = 13
(ii) 36.8 × 10
Solution:
When we multiply a decimal by 10, the point of decimal is shifted to the right by one place.
Thus,
36.8 × 10 = 368
(iii) 153.7 × 10
Solution:
When we multiply a decimal by 10, the point of decimal is shifted to the right by one place.
Thus,
153.7 × 10 = 1537
(iv) 168.07 × 10
Solution:
When we multiply a decimal by 10, the point of decimal is shifted to the right by one place.
Thus,
168.07 × 10 = 1680.7
(v) 31.1 × 100
Solution:
When we multiply a decimal by 100, the point of decimal is shifted to the right by two places.
Thus,
31.1 × 100 = 3110.0
= 3110
(vi) 156.1 × 100
Solution:
When we multiply a decimal by 100, the point of decimal is shifted to the right by two places.
Thus,
156.1 × 100 = 15610.0
= 15610
(vii) 3.62 × 100
Solution:
When we multiply a decimal by 100, the point of decimal is shifted to the right by two places.
Thus,
3.62 × 100 = 362
(viii) 43.07 × 100
Solution:
When we multiply a decimal by 100, the point of decimal is shifted to the right by two places.
Thus,
43.07 × 100 = 362
(ix) 0.5 × 10
Solution:
When we multiply a decimal by 10, the point of decimal is shifted to the right by one place.
Thus,
0.5 × 10 = 5
(x) 0.08 × 10
Solution:
When we multiply a decimal by 10, the point of decimal is shifted to the right by one place.
Thus,
0.08 × 10 = 0.8
(xi) 0.9 × 100
Solution:
When we multiply a decimal by 100, the point of decimal is shifted to the right by two places.
Thus,
0.9 × 100 = 90
(xii) 0.03 × 1000
Solution:
When we multiply a decimal by 1000, the point of decimal is shifted to the right by three places.
Thus,
0.03 × 1000 = 30
4. A two-wheeler covers a distance of 55.3 km in one litre of petrol. How much distance will it cover in 10 litres of petrol?
Solution:
Given,
Distance covered by a two-wheeler in 1-litre petrol = 55.3 Km
Now,
Distance covered by a two-wheeler in 10-litre petrol = 10 × 55.3
= 553 km
5. Find:
(i) 2.5 × 0.3
Solution:
(ii) 0.1 × 51.7
Solution:
(iii) 0.2 × 316.8
Solution:
(iv) 1.3 × 3.1
Solution:
(v) 0.5 × 0.05
Solution:
(vi) 11.2 × 0.15
Solution:
(vii) 1.07 × 0.02
Solution:
(viii) 10.05 × 1.05
Solution:
(ix) 101.01 × 0.01
Solution:
(x) 100.01 × 1.1
Solution:
