I have no end of frustration trying to do math with pen and paper. I can not seem to complete a page of working without making multiple mistakes.
I'm looking for something that will allow me to work on college-level math problems, checking my working as I go.
I've previously used LaTeX, but am open to learning a new system whether that involves sexps, APL, or something else.
I am hoping for something that, with practice, is at least as quick as pen and paper and can be converted to LaTeX. And I'm hoping for something that is going to continue to improve (maybe Lean or some large language model?)