My DD7(just turned 7) is in 2nd grade but she is doing 4th grade Math and reading. She will bring her S'pore Math or gifted kids 4th grade from Flashkids with her to school. She will do her class work first and usually finished way earlier than everyone and she works on her own thing. She was reading HP books before but now that she is done, she turns to Math.
I know it is frustrating. We have discussed with the principal and the teacher that they will allow my DD to do independent study but it means she is on her own. So far, she does not mind. She enjoys being the smartest in the class.
May be you can advocate about online studies like study island. It costs only like $60 for the whole year and your ds can advance on his own pace. CTY Math is good but kind of pricey and EPGY Math (open enrollment) is an option. But my DD likes study island because she can play games after correct answer. The school is supposed to let my DD does study island 3 days a week but it hasn't happened regularly for several excuses.
And check out superstars Math III in google. They have great problem solving questions for K-8 and your ds can choose his own level. Try aleks website for algebra.
