I have a lot of experience on math teaching这句话有没有语法上的错误？

on不对哦。
应该是in.
更正为：I have a lot of experience in math teaching.

have (…)experience in (doing) sth.有在……方面的经验

eg:I am trying to find out experience in teaching.
我在摸索教学经验。

I am quite convinced of her experience in it.
我很相信她在这方面的经验。

好像没有，experience意为经验时为不可数名词，可以用a lot of 修饰；
只是介词on不知是否正确。