I agree with brilliantcp's observation about a *general* lack of rigor in math studies in the US schools. But I don't think rushing kids through an accelerated curriculum is a good idea for anyone. For students who are not fully ready for it, rushing them would prevent them from building a solid foundation. If one compares the US math curriculum and, say, Singapore Math, there is already obvious difference in that the US math curriculum tends to be "a mile wide and an inch deep". I think the lack of depth is something that needs to be addressed, not just for advanced or gifted math students, but really for everyone. It's not that the US students are not exposed to enough math concepts, the issue is that they don't have the time to think deeply about any of those and don't do enough practices. The end result is that, even for the really good math students, they tend to have heard about many math concepts, but if you probe them a bit, you realize that they have very superficial understanding of these concepts and can't really use them in any original ways.
The accelerated curriculum doesn't really help this. It simply let's kids go through the same crappy teaching faster. I'd rather see students stay on important concepts for an extended time and really get to the bottom of things. But in schools, it's much, much easier to offer acceleration, and much harder to offer in-depth studies.
