This is a foo type of entry as a cheatsheet for me.
<p>
1. Here is how we embed math equations in the posts:

<script type="text/x-mathjax-config">
MathJax.Hub.Config({
  tex2jax: {
    inlineMath: [['$','$'], ['\\(','\\)']],
    processEscapes: true
  }
});
</script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.0/MathJax.js?config=TeX-AMS-MML_HTMLorMML" type="text/javascript"></script>

$$mean = \frac{\displaystyle\sum_{i=1}^{n} x_{i}}{n}$$
</p>