The Windows Calculator has a bunch of built-in features that aren’t present in the stock Android calculator, for example. It supports Standard, Scientific, and Programmer modes.

The Windows Calculator is now open source, and the folks at Uno Platform took the source code and put it onto Android.

For 6 years, Slovakian developer Tibor Kaputa has been the driving force behind Simple Mobile Tools — a suite of 22 basic Android apps, most of them free, produced in an open-source manner that ...