Pinion Angle Help

I put my numbers in on the picture graph. Trans down 2.75 Degrees
Driveshaft up at trans end and down at rear end 1.50 Degrees
Rear end up 1.10 Degrees
I am still lost on the calculations of up and down, where do I add and where do I subtract.
Post #5 explains it 100%. I don't know how it can be any more clear.