Is there some package or builtin emacs feature which evaluates an algebraic formula in place?
E.g. I type in the scratch buffer:
(3 + 4) * 5
and when I invoke some command on this line then I get in the buffer:
(3 + 4) * 5 = 35
It's not hard to implement, I'd just like to know of there is an existing feature which can do this.