Question

Lcm for 5 6 15 ?

Answer 1

The least common multiple is `30`.

Explanation:

List out some multiples of each number:

`5:qquad5,qquad10,quad15,quad20,quad25,quadcolor(red)30...`

`6:qquad6,qquad12,quad18,quad24,quadcolor(red)30,quad36...`

`15:quad15,quadcolor(red)30,quad45,quad60,quad75,quad90...`

We can see that the first number that all three have in common is `30`.

Therefore, this is their least common multiple. We can check our work using a calculator:

Answer 2

`LCM=2xx3xx5=30`

Explanation:

Another way to calculate LCM is to first do a prime factorization:

`5=5`
`6=2xx3`
`15=3xx5`

and now we grab the biggest grouping of each prime listed.

For instance, there is a 2 in the 6:

`LCM=2xx...`

And a 3 in the 6 and the 15. Since the biggest grouping is of a single 3, we grab one:

`LCM=2xx3xx...`

And both the 5 and the 15 have a grouping of a single 5, so we grab one of those:

`LCM=2xx3xx5=30`