the "smart" kids do seem to have those skills, though. either that, or they're being tutored on the side, or they just require fewer examples to get it
whatever the case is, i think the idea behind skipping grades is that the kid isn't learning much in the classes they're in. they may not learn much in the next level either, but it allows the school to test that they've learned what they were supposed to (from class or elsewhere), while wasting less of the student and teacher's time
that said, testing out seems like it'd be better than forcing the kids to sit through yet another math class, even if it's one level higher. more time to touch grass, or read in the library, etc.
Yeah the smart kids may need fewer examples or fewer practice reps, but very few kids can skip entirely, say, 4th grade math, and not struggle to catch up. It seems unnecessarily painful, when instead they could be taught smoothly at double the pace.
whatever the case is, i think the idea behind skipping grades is that the kid isn't learning much in the classes they're in. they may not learn much in the next level either, but it allows the school to test that they've learned what they were supposed to (from class or elsewhere), while wasting less of the student and teacher's time
that said, testing out seems like it'd be better than forcing the kids to sit through yet another math class, even if it's one level higher. more time to touch grass, or read in the library, etc.