Question

Find LCM and HCF of the integers 12, 15, and 21 by using prime factorization method.

Answer 1

Given numbers are 12, 15 and 21

Factorization of 12, 15 and 21

Here, 3¹ is the smallest power of the common factor 3.

So, HCF (12, 15, 21) = 3

2² × 3¹ × 5¹ × 7¹ are the greatest powers of the prime factors 2, 3, 5 and 7 respectively involved in the given three numbers .

LCM of these three integers = 2 × 2 × 3 × 5 × 7 = 420