If your school is willing to do next grade in pre-Algebra with the idea of Algebra in 4th I'd go for it. Worst thing that happens is he it doesn't work out and he repeats next years class. Sounds more advanced than most schools I know.
In my opinion the skill for Algebra you son can't do without solid practice is fractions. Adding, multiplying, LCD, HCM, and reducing with fractions into the two digit over three digit range until he is very comfortable and recognizes the tricks to solve problems faster. If he really has only seen some of these topics briefly in Khan & AoPS that might not be enough. I've tutored 8th grade students in Algebra that struggled primarily because they were still uncomfortable and slow at manipulating fractions. But since it sounds like your son is talking Pre-Algebra next year that should give him a lot of practice with fractions. It's usually a big topic in any Pre-Algebra class.
Last edited by bluemagic; 05/18/15 11:56 AM.
