I donot know individually if one does extra work at home, but

as in our middle school, the 5th grade math is simply skipped for advanced 5th grade advanced class. When needed they just give a simply review. Its kinda brutal that kids start to get kicked out of advanced class 2 weeks after school begins.

i think they can take more AP later on if they finish math earlier. No wonder I heard some one take 18 AP class during high school.

Well, personally I donot like the way in which public schools run. But a good public school is very competitive in terms of academy.