Question

# The HCF of 60 and 72 is 12. Find their LCM.

Hint: We have to proceed by writing each number as a product of its prime factors and then we know that the lowest common multiple is found by multiplying all the factors which appear in either list of the prime factors of both the numbers.

Prime factors of 60$\to 2 \times 2 \times 3 \times 5$
Prime factors of 72$\to 2 \times 2 \times 2 \times 3 \times 3$
$LCM{\text{ of 60 and 72 }} \to {\text{ 2}} \times {\text{2}} \times 2 \times {\text{3}} \times 3 \times 5 = 360$