Application that solves math expressions. Main features:

* Supports variables (e.g. you can do "a=5", then "a+1" and you get 6)
* Built-in basic function (like logarithms and trigonometry)
* Custom functions can be defined (e.g. "log(x,b)=log(x)/log(b)", then log(32,2) will print 5)
* Variables and functions can be edited both from the prompt and dialogs
* Can print parsing and evaluation steps.
* (Android 6.0+ only) can evaluate expressions from text selection in any application (ACTION_PROCESS_TEXT intent).
* Fully localizable - actually includes English and Italian, you can contribute yor translation with a pull request on GitHub.

Changelog:

* 1.2: updated build tools to fix crash on some Android versions.
* 1.1: added localization support and Italian translation; added ACTION_PROCESS_TEXT intent filter.
* 1.0: Initial version.

This application is based on this open source (MIT licensed) library.