Hi,
I want to share an app that I developed a couple of years ago. It is a simple calculator tool that allows you to store some formulae with variable names that you can define to your liking (if you want to test it you can download the apk + some screenshots here.
Now, I have put the source onto gitlab, but it is not usable atm (some configuration stuff with Android Studio or sth like that that I couldn’t figure out quickly).
Personally, I am done with this and I am okay whether anybody is interested in this or not, but I am willing to answer any questions if somebody wants to get it running.