Exercise 2.6
Q 1, Ex 2.6 - Fractions and Decimals - Chapter 2 - Maths Class 7th - NCERT
Find:
(i) 0.2 \times 6
Sol :
0.2 \times 6 =\dfrac{2}{10} \times 6 =\dfrac{12}{10} = 1.2
(ii) 8 \times 4.6
Sol :
8 \times 4.6 =8\times \dfrac{46}{10} =\dfrac{368}{10} = 36.8
(iii) 2.71 \times 5
Sol :
2.71 \times 5 =\dfrac{271}{100}\times 5 =\dfrac{1355}{100} = 13.55
(iv) 20.1 \times 4
Sol :
20.1 \times 4 =\dfrac{201}{10} \times 4 =\dfrac{804}{10} = 80.4
(v) 0.05 \times 7
Sol :
0.05 \times 7 =\dfrac{5}{100} \times 7 =\dfrac{35}{100} = 0.35
(vi) 211.02 \times 4
Sol :
211.02 \times 4 =\dfrac{21102}{100} \times 4 =\dfrac{84408}{100} = 844.08
(vii) 2 \times 0.86
Sol :
2 \times 0.864 =2 \times \dfrac{86}{100} =\dfrac{172}{100} = 1.72
Q 2, Ex 2.6 - Fractions and Decimals - Chapter 2 - Maths Class 7th - NCERT
Question 2
Find the area of rectangle whose length is 5.7 cm and breadth is 3 cm.
Sol :
Length = 5.7 cm
Breadth = 3 cm
Area = Length x Breadth
Area = 5.7\times 3 =17.1 cm^2
Q 3, Ex 2.6 - Fractions and Decimals - Chapter 2 - Maths Class 7th - NCERT
Find:
(i) 1.3 \times 10
Sol :
= 13
(ii) 36.8 \times 10
Sol :
= 368
(iii) 153.7 \times 10
Sol :
= 1537
(iv) 168.07 \times 10
Sol :
= 1680.7
(v) 31.1 \times 100
Sol :
= 3110
(vi) 156.1 \times 100
Sol :
= 15610
(vii) 3.62 \times 100
Sol :
= 362
(viii) 43.07 \times 100
Sol :
= 4307
(ix) 0.5 \times 10
Sol :
= 5
(x) 0.08 \times 10
Sol :
= 0.8
(xi) 0.9 \times 100
Sol :
= 90
(xii) 0.03 \times 1000
Sol :
= 30
Notes : We know that when a decimal number is multiplied by 10, 100, 1000, the decimal point in the product is shifted to the right by as many places as there are zeroes.
Q 4, Ex 2.6 - Fractions and Decimals - Chapter 2 - Maths Class 7th - NCERT
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?
Sol :
Distance covered in 1 litre of petrol = 55.3 km
Distance covered in 10 litre of petrol = 1 0 \times 55.3 = 553 km
Therefore, it will cover 553 km distance in 10 litre petrol.
Q 5, Ex 2.6 - Fractions and Decimals - Chapter 2 - Maths Class 7th - NCERT
Question 5
Find:
(i) 2.5 \times 0.3
Sol :
2.5 \times 0.3 =\dfrac{25}{10}\times \dfrac{3}{10} =\dfrac{75}{100} = 0.75
(ii) 0.1 \times 51.7
Sol :
0.1 \times 51.7 =\dfrac{}{} \times \dfrac{}{} =\dfrac{517}{100} = 5.17
(iii) 0.2 \times 316.8
Sol :
0.2 \times 316.8 =\dfrac{2}{10} \times \dfrac{3168}{10} =\dfrac{6336}{100} = 63.36
(iv) 1.3 \times 3.1
Sol :
1.3 \times 3.1 =\dfrac{13}{10} \times \dfrac{31}{10} =\dfrac{403}{100} = 4.03
(v) 0.5 \times 0.05
Sol :
0.5 \times 0.05 =\dfrac{5}{10} \times \dfrac{5}{100} =\dfrac{25}{100} = 0.025
(vi) 11.2 \times 0.15
Sol :
11.2 \times 0.15 =\dfrac{112}{10} \times \dfrac{15}{100} =\dfrac{1680}{1000} = 1.680 or 1.68
(vii) 1.07 \times 0.02
Sol :
1.07 \times 0.02 =\dfrac{107}{100} \times \dfrac{2}{100} =\dfrac{214}{1000} = 0.0214
(viii) 10.05 \times 1.05
Sol :
10.05 \times 1.05 =\dfrac{1005}{100} \times \dfrac{105}{100} =\dfrac{105525}{10000} = 10.5525
(ix) 101.01 \times 0.01
Sol :
101.01 \times 0.01 =\dfrac{10101}{100} \times \dfrac{1}{100} =\dfrac{10101}{10000} = 1.0101
(x) 100.01 \times 1.1
Sol :
100.01 \times 1.1 =\dfrac{10001}{100} \times \dfrac{11}{10} =\dfrac{110011}{1000} = 110.011
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