[kqr]

Isn't Emacs calc-mode what you're asking for? You can use it as a stand-alone application even if you don't use Emacs for anything else.

[iasay]

That’s like going to Japan to eat sushi. I’d rather make it at home :)

[kqr]

Sushi is very easy to make compared to replicating calc-mode.

It's more like going to Japan to ride a Japanese train. Would you rather build a full-scale replication in your back yard?

[iasay]

True but sometimes we do things for the journey :)