Exponents (Exercise 6.4) RD Sharma Solutions | Mathematics (Maths) Class 7 PDF Download

 Page 1


 
 
 
 
 
 
 
Exercise 6.4         Page No: 6.31 
 
1. Write the following numbers in the expanded exponential forms:  
(i) 20068 
(ii) 420719 
(iii) 7805192 
(iv) 5004132 
(v) 927303 
 
Solution: 
(i) Given 20068 
20068 = 2 x 10
4
 + 0 x 10
3
 + 0 x 10
2
 + 6 x 10
1
 + 8 x 10
0
 
 
(ii) Given 420719 
420719 = 4 x 10
5
 + 2 x 10
4
 + 0 x 10
3
 + 7 x 10
2
 + 1 x 10
1
 + 9 x 10
0
 
 
(iii) Given 7805192 
7805192 = 7 x 10
6
 + 8 x 10
5
 + 0 x 10
4
 + 5 x 10
3
 + 1 x 10
2
 + 9 x 10
1
 + 2 x 10
0
 
 
(iv) Given 5004132 
5004132 = 5 x 10
6
 + 0 x 10
5
 + 0 x 10
4
 + 4 x 10
3
 + 1 x 10
2
 + 3 x 10
1
 + 2 x 10
0
 
 
(v) Given 927303 
927303 = 9 x 10
5
 + 2 x 10
4
 + 7 x 10
3
 + 3 x 10
2
 + 0 x 10
1
 + 3 x 10
0
 
 
2. Find the number from each of the following expanded forms: 
(i) 7 × 10
4
 + 6 × 10
3
 + 0 × 10
2
 + 4 × 10
1
 + 5 × 10
0
 
(ii) 5 × 10
5
 + 4 × 10
4
 + 2 × 10
3
 + 3 × 10
0
 
(iii) 9 × 10
5
 + 5 × 10
2
 + 3 × 10
1
 
(iv) 3 × 10
4 
+ 4 × 10
2
 + 5 × 10
0  
 
Solution: 
(i) Given 7 × 10
4
 + 6 × 10
3
 + 0 × 10
2
 + 4 × 10
1
 + 5 × 10
0
 
 = 7 x 10000 + 6 x 1000 + 0 x 100 + 4 x 10 + 5 x 1  
= 70000 + 6000 + 0 + 40 + 5 
= 76045 
Page 2


 
 
 
 
 
 
 
Exercise 6.4         Page No: 6.31 
 
1. Write the following numbers in the expanded exponential forms:  
(i) 20068 
(ii) 420719 
(iii) 7805192 
(iv) 5004132 
(v) 927303 
 
Solution: 
(i) Given 20068 
20068 = 2 x 10
4
 + 0 x 10
3
 + 0 x 10
2
 + 6 x 10
1
 + 8 x 10
0
 
 
(ii) Given 420719 
420719 = 4 x 10
5
 + 2 x 10
4
 + 0 x 10
3
 + 7 x 10
2
 + 1 x 10
1
 + 9 x 10
0
 
 
(iii) Given 7805192 
7805192 = 7 x 10
6
 + 8 x 10
5
 + 0 x 10
4
 + 5 x 10
3
 + 1 x 10
2
 + 9 x 10
1
 + 2 x 10
0
 
 
(iv) Given 5004132 
5004132 = 5 x 10
6
 + 0 x 10
5
 + 0 x 10
4
 + 4 x 10
3
 + 1 x 10
2
 + 3 x 10
1
 + 2 x 10
0
 
 
(v) Given 927303 
927303 = 9 x 10
5
 + 2 x 10
4
 + 7 x 10
3
 + 3 x 10
2
 + 0 x 10
1
 + 3 x 10
0
 
 
2. Find the number from each of the following expanded forms: 
(i) 7 × 10
4
 + 6 × 10
3
 + 0 × 10
2
 + 4 × 10
1
 + 5 × 10
0
 
(ii) 5 × 10
5
 + 4 × 10
4
 + 2 × 10
3
 + 3 × 10
0
 
(iii) 9 × 10
5
 + 5 × 10
2
 + 3 × 10
1
 
(iv) 3 × 10
4 
+ 4 × 10
2
 + 5 × 10
0  
 
Solution: 
(i) Given 7 × 10
4
 + 6 × 10
3
 + 0 × 10
2
 + 4 × 10
1
 + 5 × 10
0
 
 = 7 x 10000 + 6 x 1000 + 0 x 100 + 4 x 10 + 5 x 1  
= 70000 + 6000 + 0 + 40 + 5 
= 76045 
 
 
 
 
 
 
 
(ii) Given 5 × 10
5
 + 4 × 10
4
 + 2 × 10
3
 + 3 × 10
0
 
= 5 x 100000 + 4 x 10000 + 2 x 1000 + 3 x 1  
= 500000 + 40000 + 2000 + 3 
= 542003 
 
(iii) Given 9 × 10
5
 + 5 × 10
2
 + 3 × 10
1
 
= 9 x 100000 + 5 x 100 + 3 x 10  
= 900000 + 500 + 30 
= 900530 
 
(iv) Given 3 × 10
4 
+ 4 × 10
2
 + 5 × 10
0  
= 3 x 10000 + 4 x 100 + 5 x 1  
= 30000 + 400 + 5 
= 30405