DS12 completed several of the AOPS courses using textbook only. I read that the online course is worthwhile so he recently began Intro to Number Theory online (he completed the book probably 1.5 to 2 years ago). Not sure if he forgot a lot or not but he says the course is quite challenging and he wants to repeat all of the courses online.
I was looking to slow him down a little bit and this might be a good way. We will see how this course goes.
In general, he really likes AoPS and has done a lot of FTW and Alcumus. He entered several math competitions this year and has done well.
