> Schools are more willing to differentiate learning when it comes to reading/writing than math. This is because it doesn't require different lesson plans to let kids read different books during free reading time, for example. And when grading a kids' writing, it's not hard for a teacher to focus on basic skills for kids that are slower, and more advanced grammatical nitpicks for kids who have the basics down.

Ironically, that's exactly the kind of individual-differentiation-without-group-tracking that people around here object to when it is proposed for math.

Schools are, increasingly, willing to differentiate this way for math. Conservative (in the “attached to past methods”, rather than ideological, sense, though there is considerable correlation here) factions in the populace are opposed to it, though.