Class 6 - Mathematics
Chapter - Exponents and Powers : Exercise 13.3
Top Block 1
Question: 1.Write the following numbers in the expanded form:
279404, 3006194, 2806196, 120719, 20068
Answer :
(i) 2,79,404 = 2,00,000 + 70,000 + 9,000 + 400 + 00 + 4
= 2 x 100000 + 7 x 10000 + 9 x 1000 + 4 x 100 + 0 x 10 + 4 x 1
= 2 x 105 + 7 x 104 + 9 x 103 + 4 x 102 + 0 x 101 + 4 x 100
(ii) 30,06,194 = 30,00,000 + 0 + 0 + 6,000 + 100 + 90 + 4
= 3 x 1000000 + 0 x 100000 + 0 x 10000 + 6 x 1000 + 1 x 100 + 9 x 10 + 4 x 1
= 3 x 106 + 0 x 105 + 0 x 104 + 6 x 103 + 1 x 102 + 9 x 10 + 4 x 100
(iii) 28,06,196 = 20,00,000 + 8,00,000 + 0 + 6,000 + 100 + 90 + 6
= 2 x 1000000 + 8 x 100000 + 0 x 10000 + 6 x 1000 + 1 x 100 + 9 x 10 + 6 x 1
= 2 x 106 + 8 x 105 + 0 x 104 + 6 x 103 + 1 x 102 + 9 x 10 + 6 x 100
(iv) 1,20,719 = 1,00,000 + 20,000 + 0 + 700 + 10 + 9
= 1 x 100000 + 2 x 10000 + 0 x 1000 + 7 x 100 + 1 x 10 + 9 x 1
= 1 x 105 + 2 x 104 + 0 x 103 + 7 x 102 + 1 x 101 + 9 x 100
(v) 20,068 = 20,000 + 00 + 00 + 60 + 8
= 2 x 10000 + 0 x 1000 + 0 x 100 + 6 x 10 + 8 x 1
= 2 x 104 + 0 x 103 + 0 x 102 + 6 x 101 + 8 x 100
Question: 2.Find the number from each of the following expanded forms:
(a) 8 x 104 + 6 x 103 + 0 x 102 + 4 x 101 + 5 x 100
(b) 4 x 105 + 5 x 103 + 3 x 102 + 2 x 100
(c) 3 x 104 + 7 x 102 + 5 x 100
(d) 9 x 105 + 2 x 102 + 3 x 101
Answer :
(a) 8 x 104 + 6 x 103 + 0 x 102 + 4 x 101 + 5 x 100
= 8 x 10000 + 6 x 1000 + 0 x 100 + 4 x 10 + 5 x 1
= 80000 + 6000 + 0 + 40 + 5
= 86,045
(b) 4 x 105 + 5 x 103 + 3 x 102 + 2 x 100
= 4 x 100000 + 0 x 10000 + 5 x 1000 + 3 x 100 + 0 x 10 + 2 x 1
= 400000 + 0 + 5000 + 3000 + 0 + 2
= 4,05,302
(c) 3 x 104 + 7 x 102 + 5 x 100
= 3 x 10000 + 0 x 1000 + 7 x 100 + 0 x 10 + 5 x 1
= 30000 + 0 + 700 + 0 + 5
= 30,705
(d) 9 x 105 + 2 x 102 + 3 x 101
= 9 x 100000 + 0 x 10000 + 0 x 1000 + 2 x 100 + 3 x 10 + 0 x 1
= 900000 + 0 + 0 + 200 + 30 + 0
= 9,00,230
Question: 3.Express the following numbers in standard form:
(i) 5,00,00,000
(ii) 70,00,000
(iii) 3,18,65,00,000
(iv) 3,90,878
(v) 39087.8
(vi) 3908.78
Answer :
(i) 5,00,00,000 = 5 x 1,00,00,000 = 5 x 107
(ii) 70,00,000 = 7 x 10,00,000 = 7 x 106
(iii) 3,18,65,00,000 = 31865 x 100000 = 3.1865 x 10000 x 100000 = 3.1865 x 109
(iv) 3,90,878 = 3.90878 x 100000 = 3.90878 x 105
(v) 39087.8 = 3.90878 x 10000 = 3.90878 x 104
(vi) 3908.78 = 3.90878 x 1000 = 3.90878 x 103
Mddle block 1
Question: 4.Express the number appearing in the following statements in standard form:
(a) The distance between Earth and Moon is 384,000,000 m.
(b) Speed of light in vacuum is 300,000,000 m/s.
(c) Diameter of Earth id 1,27,56,000 m.
(d) Diameter of the Sun is 1,400,000,000 m.
(e) In a galaxy there are on an average 100,000,000,0000 stars.
(f) The universe is estimated to be about 12,000,000,000 years old.
(g) The distance of the Sun from the centre of the Milky Way Galaxy is estimated to be 300,000,000,000,000,000,000 m.
(h) 60,230,000,000,000,000,000,000 molecules are contained in a drop of water weighing 1.8 gm.
(i) The Earth has 1,353,000,000 cubic km of sea water.
(j) The population of India was about 1,027,000,000 in march, 2001.
Answer :
(a) The distance between Earth and Moon = 384,000,000 m
= 384 x 1000000 m = 3.84 x 100 x 1000000
= 3.84 x 108 m
(b) Speed of light in vacuum = 300,000,000 m/s
= 3 x 100000000 m/s
= 3 x 108 m/s
(c) Diameter of the Earth = 1,27,56,000 m
= 12756 x 1000 m = 1.2756 x 10000 x 1000 m
= 1.2756 x 107 m
(d) Diameter of the Sun = 1,400,000,000 m
= 14 x 100,000,000 m = 1.4 x 10 x 100,000,000 m
= 1.4 x 109 m
(e) Average of Stars = 100,000,000,000
= 1 x 100,000,000,000
= 1 x 1011
(f) Years of Universe = 12,000,000,000 years
= 12 x 1000,000,000 years
= 1.2 x 10 x 1000,000,000 years
= 1.2 x 1010 years
(g) Distance of the Sun from the = 300,000,000,000,000,000,000 m
centre of the Milky Way Galaxy = 3 x 100,000,000,000,000,000,000 m
= 3 x 1020 m
(h) Number of molecules in a drop = 60,230,000,000,000,000,000,000
of water weighing 1.8 gm = 6023 x 10,000,000,000,000,000,000
= 6.023 x 1000 x 10,000,000,000,000,000,000
= 6.023 x 1022
(i) The Earth has Sea water = 1,353,000,000 km3
= 1,353 x 1000000 km3
= 1.353 x 1000 x 1000,000 km3
= 1.353 x 109 km3
(j) The population of India = 1,027,000,000
= 1027 x 1000000
= 1.027 x 1000 x 1000000
= 1.027 x 109