math problems

I have this very simple MSaccess 2000 database that I am building and I am stuck. I need two more fields added to the form which will have formula in them and I am not sure how to do this. I do not want it done with code because I know absolutely nothing about that. If anybody could help me I could email it to them. I sure would appreciate any help at all. Im sure for someone that knows MSaccess good it wouldn't take them long

 

If possible, better to keep the whole topic on here so you can get suggestions from several people and so any who look at the topic later can benefit.

What sort of calculations do you need to do? What format are your number fields in?