Seriously, if the pace is way too slow, and he already has a good grasp of most of the material, perhaps math class every other day with instructions from the teacher to work ahead to cover the next day's assignments really would work for him, and give him the best of both worlds. Then, hopefully, he'd only have to listen to the explanations of things he already knows once, and he could still do his pullouts during math and spelling time, etc. on the days he doesn't go to math class, or he could use the lower grade's math time to work in the library or in the office on his next day's math assignments for the higher class. The only drawback I can really see is that only being there half the time would draw attention to the fact that he wasn't being treated like a regular member of the class.
