Well, yes and no. I can only speak from my experience of doing grades 1 through 7 in a Ukrainian school and then 8-12 in Canada. The year I went into school I was placed into the "Sapling" (Rostok) programme, which was a very accelerated "experimental" programme. I remember that in Grade 2 we were learning Venn Diagrams and basic set notation. And so on. By Grade 4 we were allegedly 2-3 years ahead of the "regular" system. Now when I got to Canada in Grade 8 I honestly did not know what to do with myself, the level of math I was exposed simply eclipsed what was being taught (Integer beads, the fuck?) and this has been my general experience of the school system up until Grade 12 where we started doing Calculus (which in "Sapling" was supposed to be done in Gr. 9-10).

The problem, I think, is not that kids can't learn (in fact the amount neuroplasticity in young children is simply off the charts, to the point where 6-7 year olds who can play really good violin are not something special), but is that the educational system simply does want to go there, to increase the levels of math taught in schools.

I believe this is also called 'business as usual'... but you actually put it much better.

Coming from Delaware, most every school, public and private, that I know of partitions students into math courses based on achievement level. They typically don't let students go "out of grade" by more than a year, but that's a sizable amount in high school (e.g., some juniors learning the same material as some freshman). I didn't know there were places that didn't do it that way-- do your local schools not have advanced math & regular math tracks for their students?

Most schools do it at the high school and maybe jr. high level but I have never heard of this happening at the elementary level. We had separate math "groups" in elementary school but this was still within the same classroom and the more advanced group simply learned more about the concepts we were covering.

(Born, raised, and educated in California)

you're totally right -- I was talking about the jr. high and high school levels. Occasionally you'll see exceptions and some kids will be allowed up a grade or two in elementary, but it's not embedded in the process the way it is in jr. high and high school.

I haven't heard of this being attempted, though I would surprised to find that it hasn't.

However, one reason it might be avoided is due to the potential negative effects tracking [1] strategies may have on some students. In my public school district, any form of tracking at the elementary level was difficult to implement due to pushback from parents, even in situations where the educators felt it was beneficial.

1 - http://en.wikipedia.org/wiki/Tracking_%28education%29

The elementary school that my kids attended had a couple of approaches. In higher grades, teachers paired up, and swapped classrooms so the stronger math teacher taught math to both classes. They also had "math specialists" who could float from one classroom to another, along with other kinds of special teachers and aides of various stripes.

A decent fraction of the kids learned math at home, making it hard to assess how well the school was actually doing.

I imagine that anywhere it is suggested it would be shot down by logistical concerns as well as sociological concerns of mixing age groups. You need a relatively common level of maturity, etc.