Question

Find the LCM and HCF of the following integers by applying the prime factorisation method.

12, 15 and 21

Answer 1

12 = 2 × 2 × 3

15 = 3 × 5

21 = 3 × 7

H.C.F of 12, 15 and 21 = 3

L.CM of 12, 15 and 21 = 2 × 2 × 3 × 5 × 7

L.C.M of 12, 15 and 21 = 420