RD Sharma solution class 7 chapter 6 Exponents Exercise 6.3

Exercise 6.4

Page-6.31

Question 1:

Write the following numbers in the expanded exponential forms:
(i) 20068
(ii) 420719
(iii) 7805192
(iv) 5004132
(v) 927303

Answer 1:

We have
(i) 20068 = 2 x 10⁴ + 0 x 10³ + 0 x 10² + 6 x 10¹ + 8 x 10⁰
(ii) 420719 = 4 x 10⁵ + 2 x 10⁴ + 0 x 10³ + 7 x 10² + 1 x 10¹ + 9 x 10⁰
(iii) 7805192 = 7 x 10⁶ + 8 x 10⁵ + 0 x 10⁴ + 5 x 10³ + 1 x 10² + 9 x 10¹ + 2 x 10⁰
(iv) 5004132 = 5 x 10⁶ + 0 x 10⁵ + 0 x 10⁴  4 x 10³ + 1 x 10² + 3 x 10¹ + 2 x 10⁰
(v) 927303 = 9 x 10⁵ + 2 x 10⁴  + 7 x 10³ + 3 x 10² +  0 x 10¹ + 3 x 10⁰

Note: a⁰ = 1

Question 2:

Find the number from each of the following expanded forms:
(i) 7 × 10⁴ + 6 × 10³ + 0 × 10² + 4 × 10¹ + 5 × 10⁰
(ii) 5 × 10⁵ + 4 × 10⁴ + 2 × 10³ + 3 × 10⁰
(iii) 9 × 10⁵ + 5 × 10² + 3 × 10¹
(iv) 3 × 10⁴ + 4 × 10² + 5 × 10⁰

Answer 2:

We have

(i) 7 × 10⁴ + 6 × 10³ + 0 × 10² + 4 × 10¹ + 5 × 10⁰
    = 7 x 10000 + 6 x 1000 + 0 x 100 + 4 x 10 + 5 x 1 = 76045

(ii) 5 × 10⁵ + 4 × 10⁴ + 2 × 10³ + 3 × 10⁰
      =  5 x 100000 + 4 x 10000 + 2 x 1000 + 3 x 1 = 542003

(iii) 9 × 10⁵ + 5 × 10² + 3 × 10¹
        = 9 x 100000 + 5 x 100 + 3 x 10 = 900530

(iv) 3 × 10⁴ + 4 × 10² + 5 × 10⁰
     = 3 x 10000 + 4 x 100 + 5 x 1 = 30405

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