This mod is very simple to use, stop Alt + Tabbing and just press F9 in game for access to a simple calculator. There is no milestone to unlock, no item to hold just hit F9 and run a calculation. Works with your numpad and with your mouse. Simply put it is a simple calculator!
Made by Rusketh aka MarcusWithSpots
Special Thanks to Deantendo for the amazing graphical work.
To report a bug with this mod, post your bug report on the GitHub issue's page. Please also do this for sugestions instead of via DM's, (dm's not posted on github get ignored).