[toomim]

I would totally use this if it were an extension to Emacs. I keep lots of calculation results in text files, and edit them in emacs, but I don't want to use a totally separate app whenever I want to enter and calculate some math within a text file.

[joeman1000]

Check out calc (M-x calc RET). Full RPN calculator built into emacs, with matrix and symbolic solving capabilities. Best calculator I have ever used.

[unhammer]

Try https://blog.sulami.xyz/posts/literate-calc-mode/ I use it quite often, very handy

[toomim]

Wow cool! I'm sold! Downloading it now. :)

[kleiba]

org-mode tables have spreadsheet-like capabilities, i.e., they support formulas.