I have a semi-made desk calculator with prefix notation.
You can make it an alias of * , / etc, so ...
$ * 4 6
24
$
It would keep it's own stack, but let a persistent process do the actual maths.
The persistent process could almost any repl of python, ruby etc.
Or use a 'real' calculator like Pike's ivy; https://aplwiki.com/wiki/Ivy