# What is the LCM of 3, 5, 15, 16?

240

#### Explanation:

For LCM problems, I like to do a prime factorization first:

$3 = 3$
$5 = 5$
$15 = 3 \times 5$
$16 = 2 \times 2 \times 2 \times 2$

And now the LCM will have all the primes listed.

So - we have a 3 from the 3. We have a 5 from the 5. The 3 and 5 of the 15 are already listed, so we can move on to the 16 which has four 2s. So the LCM is:

$3 \times 5 \times 2 \times 2 \times 2 \times 2 = 15 \times 16 = 240$

$3 \times 80 = 240$
$5 \times 48 = 240$
$15 \times 16 = 240$