You can add math to these pages as you would with LaTeX via MathJax.
Use \$…\$ to enclose inline mathematics, as in $x\in S$. Use \[...\] to enclose display mathematics, such as the following.\[x\in S\]
You can alternately use double dollar signs for display equations, as \$\$…\$\$, or \(…\) for inline equations.
In case you aren’t familiar with LaTeX math, you can see a short guide here [PDF].