Math functions, none. It is on our to do list, and we do already have a basic calculator in our community repositories, but KnightOS won't be suitable for real maths any time soon. Of course you're free to do something about that if you know how to - we would be more than grateful for your help!
On programming languages, we have a great assembly runtime at the moment, and we're working on supporting C, which is mostly working at the moment. Also, we have plans for brainfuck and kpy (which is a language we are designing, based on Python), and potentially Lisp and Lua.
It is possible to install it on your calculator if you want, but I personally wouldn't recommend doing that on your main calculator if you need it for school or university. It won't break your calculator or anything, but it just isn't that suitable for real mathematics at the moment. However, you can give it a shot in an emulator if you want, of course!
You can find more information on our site, knightos.org
, or our wiki, which is linked on there.