Of course you can parse, interpret it, and show the result. But this is kind of boring.
I can advise one "exotic" alternative: wrap the input in C# code, compile it using CodeDOM, execute (you will have to use a separate Application Domain, to avoid memory leak! see below), and show the result, if it was successful, otherwise show compilation error.
Please see my past answers:
code generating using CodeDom
Create WPF Application that uses Reloadable Plugins...
Not a very simple solution, but you can do a lot more with that.
If something is not quite clear, I'll gladly explain. It works.