Say what?
It's, wait for it peeps....
ALGEBRA
There are very definite rules to follow, rules that are internationally agreed upon.
This was never a programming question, it was always an algebra problem.
Rather than run off and look at the first site google spat out, I asked a couple of people with PhD's in maths, physics, accounting and economics.
Ok, the economics prof was kinda vague, but hey, it's not like a real science anyway!
I let the Math prof read this topic last night and she was still laughing about this morning!