I think that's a brilliant idea. They key to teaching a kid anything is to make it interesting for them...and I haven't come across a boy who hasnt been somewhat interested in Yu-Gi-Oh!
My boys have some they don't use...if decide to go with this method of teaching they've volunteered to send you some of them.
Well, they read about what you were trying to do with your student, and they thought that it was a good idea...so they said to tell you that they'd let him have some of their cards that they don't use or have duplicated if he wanted them. Davey in particular was quite moved - said he couldn't imagine someone not being able to do math properly and that learning with Yu-Gi-Oh! sounded like it was fun.
Will do. I'm sure they'll be tickled that you acknowledged them!