Nice effort, but...
...I'm not too sure that calculator has much use whatsoever to the average NG user. Seriously, its a calculator with basic functions wow!!! Those are the kind of operations that I can do in my head. At least a scientific calculator would've been cool too see. Or, better yet, a graphing calculator :P (though, calculators still dont have much use here...after all you cant actually bring this with you to school/everyone that's in school most likely has a calculator anyway)