Thanks for the quick feedback everyone!
DS did both 'DragonBox'es' last year in a couple hours! I did check his iPad just now, I see he didn't get 3 stars at every level so he can go back and do that bit. He loved the game (agree, very addictive) and we couldn't believe how quick he picked it up.
I have not heard of
http://www.borenson.com but will be checking it out ASAP... the iPad aspect is both convenient and fun.
If we go AOPS, I assume we start with pre-Algebra? Most likely, we can not do the online course because of timing but maybe independent study with offer us more flexibility anyway. I agree, we will end up at AOPS at some point anyway, why not now.
Thank you again!!!
