Exercise 13.3 - Chapter 13 Exponents & Powers class 7 ncert solutions Maths - SaraNextGen [2024-2025]
Updated By SaraNextGen
On April 24, 2024, 11:35 AM
Question 1:
Write the following numbers in the expanded forms:
279404, 3006194, 2806196, 120719, 20068
Answer:
279404 = 2 × 105 + 7 × 104 + 9 × 103 + 4 × 102 + 0 × 101 + 4 × 100
3006194 = 3 × 106 + 0 × 105 + 0 × 104 + 6 × 103 + 1 × 102 + 9 × 101 + 4 × 100
2806196 = 2 × 106 + 8 × 105 + 0 × 104 + 6 × 103 + 1 × 102 + 9 × 101 + 6 × 100
120719 = 1 × 105 + 2 × 104 + 0 × 103 + 7 × 102 + 1 × 101 + 9 × 100
20068 = 2 × 104 + 0 × 103 + 0 × 102 + 6 × 101 + 8 × 100
Question 2:
Find the number from each of the following expanded forms:
(a) 8 × 104 + 6 × 103 + 0 × 102 + 4 × 101 + 5 × 100
(b) 4 × 105 + 5 × 103 + 3 × 102 + 2 × 100
(c) 3 × 104 + 7 × 102 + 5 × 100
(d) 9 × 105 + 2 × 102 + 3 × 101
Answer:
(a) 8 × 104 + 6 × 103 + 0 × 102 + 4 × 101 + 5 × 100
= 86045
(b) 4 × 105 + 5 × 103 + 3 × 102 + 2 × 100
= 405302
(c) 3 × 104 + 7 × 102 + 5 × 100
= 30705
(d) 9 × 105 + 2 × 102 + 3 × 101
= 900230
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) 50000000 = 5 × 107
(ii) 7000000 = 7 × 106
(iii) 3186500000 = 3.1865 × 109
(iv) 390878 = 3.90878 × 105
(v) 39087.8 = 3.90878 × 104
(vi) 3908.78 = 3.90878 × 103
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 the Earth is 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, 000 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) 3.84 × 108 m
(b) 3 × 108 m/s
(c) 1.2756 × 107 m
(d) 1.4 × 109 m
(e) 1 × 1011 stars
(f) 1.2 × 1010 years
(g) 3 × 1020 m
(h) 6.023 × 1022
(i) 1.353 × 109 cubic km
(j) 1.027 × 109
Also Read : Exercise-14.1-Chapter-14-Symmetry-class-7-ncert-solutions-Maths
