mean to do后面接的是不定式；mean doing后面接的是动词ing；mean doing sth，其主语通常是指事物的sth；mean to do sth，其主语通常是表示人的名词或代词。

So, what does it mean to do a matrix product?

那么，矩阵乘法是什么意思？

I didn't mean to do things that I've done.

我不是说去做我已经做过的事情。

Pushing or pulling, however, does not necessarily mean doing work.

然而，推或拉未必意味着作功。

Balance does not mean doing everything.

平衡并不意味着努力追求每件事情。