rpCalc Features
- Uses reverse polish notation, similar to most Hewlett-Packard calculators.
 - The buttons can be clicked or tapped, or users can type the numbers, operators or command text on any key.
 - All four RPN registers are shown in the main display.
 - An algebraic history of recent calculations can be shown.
 - Has the same appearance and interface on Android, Linux, Windows, and the web.