Question 4 - Figure it out - Page 110, 111 - Chapter 5 Class 6 - Prime Time (Ganita Prakash)

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Question 4 (a) Find the common factors of: (a) 20 and 28 Factors of 20 1 × 20 = 20 2 × 10 = 20 4 × 5 = 20 5 × 4 = 20 We stop here as 4 & 5 have occurred earlier So factors of 20 are 1, 2, 4, 5, 10, 20 Factors of 28 1 × 28 = 28 2 × 14 = 28 4 × 7 = 28 7 × 4 = 28 We stop here as 4 & 7 have occurred earlier So factors of 28 are 1, 2, 4, 7, 14, 28 So, Common factors are 1, 2, 4 Question 4 (b) Find the common factors of: (b) 35 and 50 Factors of 35 1 × 35 = 35 5 × 7 = 35 7 × 5 = 35 We stop here as 7 & 5 have occurred earlier So factors of 35 are 1, 5, 7, 35 Factors of 50 1 × 50 = 50 2 × 25 = 50 5 × 10 = 50 10 × 5 = 50 We stop here as 5 & 10 have occurred earlier So factors of 50 are 1, 2, 5, 10, 25, 50 So Common factors are 1, 5 Question 4 (c) Find the common factors of: (c) 4, 8 and 12 Factors of 4 1 × 4 = 4 2 × 2 = 4 4 × 1 = 4 We stop here as 1 & 4 have occurred earlier So factors of 4 are 1, 2, 4 Factors of 8 1 × 8 = 8 2 × 4 = 8 4 × 2 = 8 We stop here as 2 & 4 have occurred earlier So factors of 8 are 1, 2, 4, 8 Factors of 12 1 × 12 = 12 2 × 6 = 12 3 × 4 = 12 4 × 3 = 12 We stop here as 4 and 3 have occurred earlier So factors of 12 are 1, 2, 3, 4, 6, 12 So, common factors are 1, 2, 4 Question 4 (d) Find the common factors of: (d) 5, 15 and 25We find factors of 5, 15 and 25 separately Factors of 5 1 × 5 = 5 5 × 1 = 5 We stop here as 1 & 5 have occurred earlier So factors of 5 are 1, 5 Factors of 15 1 × 15 = 15 3 × 5 = 15 5 × 3 = 15 We stop here as 3 & 5 have occurred earlier So factors of 15 are 1, 3, 5, 15 Factors of 25 1 × 25 = 25 5 × 5 = 25 25 × 1 = 25 We stop here as 25 and 1 have occurred earlier So factors of 25 are 1, 5, 25 So Common factors are 1, 5