I forgot about dc! A NetBSD instance I have still has it. Love going back in time to these original utilities.
See you later, alliterator.
Here's the NetBSD man page: https://man.netbsd.org/dc.1
And have used bc a lot.
Check out the useful bc -l option.
Here is the page for bc:
https://en.m.wikipedia.org/wiki/Bc_(programming_language)
which is mentioned in the dc page's See Also section, which is what I alluded to in my earlier comment above, i.e. that bc is built on dc.
See the History section of the bc page.