Question

Using prime factorization, find the HCF and LCM of 21, 28, 36, 45.

Answer 1

Prime factors of 21, 28, 36, 45

21 = 3 × 7

28 = 2 × 2 × 7 = 2² × 7

36 = 2 × 2 × 3 × 3 = 2² × 3²

45 = 5 × 3 × 3 = 5 × 3²

HCF(21, 28, 36, 45) = 1

LCM (21, 28, 36, 45) = 2² × 3² x 5 × 7 = 1260