How to install APK / APKS / OBB file on Android
european abacus (calculator), nothing more just abacus
just for fun, free
G-sensor supported - rolling knuckles abacus
This app uses advertising, but do not use push notification now.
You can buy the adfree version here: https://play.google.com/store/apps/details?id=draziw.adfree.abacus