I need to know how to do calculations based off multiple fields and then have the result display in a results filed.

I found this thread talking about it but, it seems like it should be easier than this, am I wrong?

http://www.gravityhelp.com/forums/topic/loan-calculator

The calculations are very simple>

(a+b)

(b-c)

(a/c)

(c*b)

Can I get a little direction on this please?

Shawn