The Calculator Assignment

Your assignment is to re-invent google calculator. Points

10 points - does not let me call exit() or any other function.
2 point - does basic math
2 point - translates "thousand", "million", and "billion".
2 point - uses a regular expression
2 point - Knows that 'c' is 300,000. i.e. "c / 20" says "15,000"
2 point - uses an object with at least two methods and at least two member variables.
2 point - Can convert between pounds and kg

This assignment can cause a security hole. If you have a security hole, you get a zero and I yell at you alot. Do not leave this code on the web. Do not leave developmental versions of this code around. It's -3 points if I have to yell at you for this the first time, and an automatic zero the second time.