Hi, recently I wrote a simple calculator in RKP format. You can find it the Download section > Tools
or click
here.
It has some basic functions like division, sum or square root. It has a limitation of 7 digits (including these after the decimal point). It is caused by limitation of the compiler which supports 4-byte Float data type.
I've done it for practice purposes as I am aware that such an app is not very useful. I will upload a source code to study for those who are beginners in C and are willing to start developing some tools.