Question 4 - Page 120 - Prime Factorisation - Chapter 5 Class 6 - Prime Time (Ganita Prakash)

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Question 4 - Page 120 Find the prime factorisation of these numbers without multiplying first a. 56 × 25 b. 108 × 75 c. 1000 × 81Basically we find prime factorisation of each of the numbers separately and then multiply it Let’s do it one by one Prime Factorisation of 56 × 25 ∴ 56 = 2 × 2 × 2 × 7 ∴ 25 = 5 × 5 = 52 Now, Prime Factorisation of 56 × 25 = Prime factorization of 56 × Prime Factorization of 25 = 23 × 7 × 52 = 23 × 52 × 7 Prime Factorisation of 108 × 75 Now, Prime Factorisation of 108 × 75 = Prime factorization of 108 × Prime Factorization of 75 = 22 × 33 × 3 × 52 = 22 × 34 × 52 Prime Factorisation of 1000 × 81 ∴ 1000 = 2 × 2 × 2 × 5 × 5 × 5 = 23 × 53 ∴ 81 = 3 × 3 × 3 × 3 = 34 Now, Prime Factorisation of 1000 × 81 = Prime factorization of 1000 × Prime Factorization of 81 = 23 × 53 × 34 = 23 × 34 × 53 = 23 × 7