Converting mathematical expressions between markdown, latex, and html is relatively straightforward using tools such as pandoc. This page has useful instructions for implementing mathjax within the jekyll template on github pages, allowing easy conversion from markdown to html.
For a given page (such as this post) mathjax is implemented by setting math: true at the beginning of the page, for example:
---
layout: post
title: MathJax on GitHub Pages
subtitle: Converting from markdown to html
tags: [math,github]
math: true
---
This allows us to use latex-style syntax to create equations, such as:
\[a^2 + b^2 = c^2\] \[E = mc^2\]