BTW: there is another obstacle aside from typing issues: readability problems and similarities between operators and ordinary characters with computer fonts.

In case of manually written math equations (or LaTeX-ones) operators are easy distinguishable from arguments. They have a different sizes too.

For example, "result = axe" and "result = a×e" in many cases looks the same and, even in my browser, with font larger, than ones usually used by my colleagues, they are very hard to distinguish. Difference between "result a÷n" and "result a-b" can be spot easier, but it depends on two one-pixel dots.

Ok that was only a mumbling of malcontent - in fact we all know that we all have a sharp, young eyes and we never will be tired or distracted, I'm pretty sure of that. ;)