Punjab State Board PSEB 7th Class Maths Book Solutions Chapter 13 Exponents and Powers Ex 13.3 Textbook Exercise Questions and Answers.
PSEB Solutions for Class 7 Maths Chapter 13 Exponents and Powers Ex 13.3
1. Write the following numbers in the expanded exponential form :
(i) 104278
Solution:
104278 = 1 × 105 + 4 × 103 + 2 × 102 + 7 × 101 + 8 × 100
(ii) 20068
Solution:
20068 = 1 × 104 + 6 × 101 + 8 × 100
(iii) 120719
Solution:
120719 = 1 × 105 + 2 × 104 + 7 × 102 + 1 × 101 + 9 × 100
(iv) 3006194
Solution:
3006194 = 3 × 106 + 6 × 103 + 1 × 102 + 9 × 101 + 4 × 100
(v) 28061906
Solution:
28061906 = 2 × 107 + 8 × 106 + 6 × 104 + 1 × 103 + 9 × 102 + 6 × 100
2. Find the number from each of the following expanded form :
(i) 4 × 104 + 7 × 103 + 5 × 102 + 6 × 101 + 1 × 100
Solution:
4 × 104 + 7 × 103 + 5 × 102 + 6 × 101 + 1 × 100
= 40000 + 7000 + 500 + 60 + 1
= 47561
(ii) 3 × 104 + 7 × 102 + 5 × 100
Solution:
3 × 104 + 7 × 102 + 5 × 100
= 30000 + 700 + 5 × 1
= 30705
(iii) 4 × 105 + 5 × 103 + 3 × 102 + 2 × 100
Solution:
4 × 105 + 5 × 103 + 3 × 102 + 2 × 100
= 400000 + 5000 + 300 + 2 × 1
= 4053202
(iv) 8 × 107 + 3 × 104 + 7 × 103 + 5 × 102 + 8 × 101
Solution:
8 × 107 + 3 × 104 + 7 × 103 + 5 × 102 + 8 × 101
= 80000000 + 30000 + 7000 + 500 + 80
= 80037580
3. Express the following numbers in standard form :
(i) 3,43,000
Solution:
3.43 × 105
(ii) 70,00,000
Solution:
7.0 × 106
(iii) 3,18,65,00,000
Solution:
3.1865 × 109
(iv) 530.7
Solution:
5.307 × 102
(v) 5985.3
Solution:
5.9853 × 103
(vi) 3908.78
Solution:
3.90878 × 103
4. Express the number appearing in the following statements in standard form :
(i) The distance between the earth and die moon is 384,000,000 m
Solution:
3.84 × 108
(ii) The diameter of the earth is 1,27,56,000 m.
Solution:
1.2756 × 197 m
(iii) The diameter of the sun is 1,400,000,000 m.
Solution:
1.40 × 109 m
(iv) The universe is estimated to be about 12,000,000,000 years old.
Solution:
1.2 × 1010 years
(v) Mass of uranis is 86,800,000, 000,000,000,000,000,000 kg
Solution:
8.68 × 1028 kg.
5. Compare the following numbers :
(i) 4.3 × 1014 ; 3,01 × 1017.
Solution:
Given numbers are 4.3 × 1014 and 3.01 × 1017 since the numbers are in standard form. As the power of 10 in 3.01 × 1017 is greater than the power of 10 in 4.3 × 1014.
∴ 3.01 × 1017 > 4.3 × 1014
(ii) 1.439 × 1012 ; 1.4335 × 1012.
Solution:
1.439 × 1012 ; 1.4335 × 1012
The numbers are in standard form
As 1.439 > 1.433
∴ 1.439 × 1012 > 1.4335 × 1012