The sum of three consecutive even numbers is 54. If the middle number is m, find the value of m.

If the middle even number is $m$, then the even number before it is $m-2$, and the even number after it is $m+2$.
The three consecutive even numbers are $m-2$, $m$, and $m+2$.

The sum of these three numbers is 54.

Combine the terms on the left side:

Divide both sides by 3:

The value of $m$ is $\boxed{\text{18}}$.