It still doesn't fix the fact that by that time, those students are still starting with 8 years' worth of hash for a math foundation.
The pace at the high school level would still need to be differentiated, granted-- but the real issue is that NO amount of slowing the pace can compensate adequately for not having learned basic number sense in 1st through 4th grade.
The mathy kids are fine-- they just need better opportunities to go further, faster. The problematic side of things is actually on the other end of the distribution-- mostly.
There are those kids who COULD be competent if they'd had reasonably good instruction, but aren't because they have not. My DD is a kid who could have been one of those, probably-- except that we intervened early and often when we saw it happening.
