Question

Find the LCM and HCF of the following integers by applying the prime factorization method: $12,15and21$.

Answer 1

Finding HCF and LCM of 12, 15 and 21:

Factorization of 12, 15 and 21

$12=2\times 2\times 3$$=2^2\times 3$

$15=3\times 5$

$21=3\times 7$

HCF = 3

LCM = $2\times 2\times 3\times 5\times 7=420$

Hence, HCF = $3$ and LCM = $420$.