A no-nonsense scientific calculator app.
It has all the functions you'd come to expect from a scientific calculator app.
The project itself was originally a school assignment. After submitting, I was quite happy with it, but I knew it had the potential to be more.
In the end, I think I rewrote and/or restructured every aspect of the existing project until I was happy to at the very least show it. Afterwards, I did a large amount of tweaks and testing, before I thought that maybe it was worth uploading to the play store.
It also served as my first exposure to releasing an app "properly", and it all went relatively smoothly.