Hi Nick - having been a teacher for many years I have to add here is that math is hard if things haven;t been broken down, or modeled for a student. If your son has been switching off, a coping mechanism, catching up will be hard, unless you can nut out where he's not comprehending. Have a chat with his teacher and you might find that you can help at home. Easy, easy. IT may be that he;s more inclined toward literacy. What are your thoughts?
Just another thought before I get back ito my box. Have a look at Howard Gardenr's Multiple Intelligences.