Ok, just found
-pbchess: Launcher for Qt apps with chess, checkers, reversi, sokoban, gomoku, notepad, a calculator, a file manager, and OPDS browser, Dropbox integration, USBnet, a simple terminal, a port of Coolreader and the ability to add your own apps. from the kobo hack and utilities Index
https://www.mobileread.com/forums/sh...d.php?t=295612
I don't know what kind of calculator it is, but graph89 is a full fledged graphing calculator with CAS (computer algebra system) - so that would be
awesome if it could be done. Anyone?