I found a site that checks blog readability level. As you can see on the image below, Math Pages readability level is High School:
Since I want this blog to be readable for as much people as possible, this is a good result. I did a similar test when I only started blogging and the result was "Advanced degree" - which was rather surprising.
However, some of the topics I mention on this blog need better knowledge of math that what you get in school (at least in Israel) so the result is not very accurate.