What is the least common multiple of 6 and 9?

Apr 5, 2016

$18$.

Explanation:

Go up in multiples of either $6$ or $9$. so for $6$, there is:

$6$, $12$, $\textcolor{b l u e}{18}$, $24$...

for $9$, there is:

$9$, $\textcolor{b l u e}{18}$, $27$, $36$...

and find the earliest or lowest number that occurs in both, which is $18$.

Jul 26, 2017

The least common multiple (LCM) of $6$ and $9$ is $18$ and the explanation is down below!

Explanation:

I always take the first 5 multiples of each number and write them down. And if we don't our LCM in there, then I write down the next five multiples! So let's start, shall we?

(First 5) Multiples of $6$:
$6 , 12 , 18 , 24 , 30$

(First 5) Multiples of $9$:
$9 , 18 , 27 , 36 , 45$

Now, we have to see if there is any common number in the numbers. If we do, we have to make sure that there isn't any other number lower than that that $6$ and $9$ go into!

(First 5) Multiples of $6$:
$6 , 12 ,$$\textcolor{b l u e}{18}$$, 24 , 30$

(First 5) Multiples of $9$:
$9 ,$$\textcolor{b l u e}{18}$$, 27 , 36 , 45$

There isn't any number before $18$ that $6$ and $9$ both go into, so $18$ is the LCM of $6$ and $9$! Now we don't need to write down anymore multiples. :)

Source: My knowledge!

I hope that helps you!