Hi, this post is particularly destined, because of it's nature, to those who are going to attend stage 1. I found this PDF file which is a book for potentiall ATC explaining how to resolve math operations up to the required standards to pass the selection process. Personally, I think it's worth looking at. Hope it helps.
**AT-SAT Math Prep** (DOWNLOAD)
You have to sign up/in the forum to able to download the wretched file, bit of a nuisance but don't hesitate in doing so if you are weak on maths.