I made a fully functional calculator in Oxygen Not Included
(I don't know why the screenshots are so bright)
After more than 60 hours of building, I've completed this automation masterpiece! It features all four basic single digit operations.
I deconstructed a total of 72.4 tons of refined metal, but I can't say how much metal is used in the calculator itself because the game keeps crashing on me when I deconstruct the build.
You only need to toggle the switch once to enter something (not on and off again), and always enter the whole equation before hitting the equal sign, otherwise it can lead to unwanted behavior. (It won't break it though)
I've uploaded the save to Google Drives, although I don't know how to load it.