The main reason that I did not write much in my blog is that I did not know how to use LaTeX in a blog post.

It turns out that the answer is quite simple. Somehow I just did not figure out this easy solution. Anyway, here it is — using MathJax for equations, for example,

$x^2+y^2=z^2$

where $$x, y$$ and $$z$$ are three variables.