Question

Using prime factorization, find the HCF and LCM of  12,15, 21 .

Answer 1

12 = 2 × 2 × 3 = 2² × 3
15 = 3 × 5
21 = 3 × 7
HCF = product of smallest power of each common prime factor in the numbers = 3
LCM = product of greatest power of each prime factor involved in the numbers

= 2² × 3 × 5 × 7 = 420