Fun Class Activity:
Fun facts: The 'less than or equal to' symbol, or $\le$, is written in $\LaTeX$ as
$\le$, and the 'greater than or equal to' symbol, or $\ge$, is written in $\LaTeX$ as $\ge$.
So $S = \{2n\ |\ 0 \le n \le 5\}$ is written as
$S = \{2n\ |\ 0 \le n \le 5\}$.
The spaces that we add around the $|$ symbol (
$\ |\ $) prevent the notation from being squashed, as in $S = \{2n | 0 \le n \le 5\}$ and $S = \{2n | 0 \le n \le 5\}$.