This is interesting, but I doubt anything will ever come up in my lifetime that is even close to replacing Emacs Calc for me. I still consider it to be the best scientific calculator ever written. It's crazy that many Emacs users aren't even aware that it exists. It comes with an almost ridiculously extensive manual, complete with exercises and everything:

https://www.gnu.org/software/emacs/manual/html_mono/calc.htm...

It's probably overkill for most people, and I'm sad that I don't get to use it as much as when I was a student, but it's still a beautiful rabbit hole to fall into. And it works in a terminal just fine. :-)