Question

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

$12,15$ and $21$.

Answer 1

We can factorize as $12=2\times 2\times 3$
$15=3\times 5$
$21=3\times 7$
HCF $=3$
LCM $=2\times 2\times 3\times 5\times 7=420$