Question 2 - Page 122 - Uses of Prime Factorisation - Chapter 5 Class 6 - Prime Time (Ganita Prakash)

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Question 2 - Page 122 – (a) Is the first number divisible by the second? Use prime factorisation. a. 225 and 27 Finding prime factorisations of both Therefore, 225 = 3 × 3 × 5 × 5 27 = 3 × 3 × 3 Since 225 has (3 × 3) but not (3 × 3 × 3) – an extra 3 is missing Thus, 225 is not divisible by 27 Question 2 - Page 122 – (b) Is the first number divisible by the second? Use prime factorisation. b. 96 and 24 Therefore, 96 = 2 × 2 × 2 × 2 × 2 × 3 24 = 2 × 2 × 2 × 3 Now, we can write 96 = (2 × 2 × 2 × 3) × 2 × 2 96 = 24 × 2 × 2 Thus, 96 is divisible by 24 Question 2 - Page 122 – (c) Is the first number divisible by the second? Use prime factorisation. c. 343 and 17Therefore, 343 = 7 × 7 × 7 17 = 17 Since 17 is not in 343 Thus, 343 is not divisible by 17 Finding prime factorisations of both Question 2 - Page 122 – (d) Is the first number divisible by the second? Use prime factorisation. d. 999 and 99Finding prime factorisations of both Therefore, 999 = 3 × 3 × 3 × 37 99 = 3 × 3 × 11 Since 11 is not in 999 Thus, 999 is not divisible by 99