#### Answer

$\left\{1, 2, 3, ..., 28, 29, 30\right\}$

#### Work Step by Step

$N$ is the set of counting or natural numbers.
Natural numbers are $1, 2, 3, ...$
The value of $x$ is less than or equal to 30.
This means that the possible values of $x$ are $1, 2, 3, ...28, 29, 30$.
The roster method lists down all the elements of the set.
Thus, writing the given set using the roster method gives:
$\left\{1, 2, 3, ..., 28, 29, 30\right\}$