Our kids are using IXL to supplement English in 4th and 5th grade, and Khan to supplement math in 5th and 8th grade. Unfortunately Khan is all-or-nothing so if the boys figure out how to get at video games, it turns into cat-and-mouse with them. You need to see progress on Khan and watch whether they are completing their coursework. If you don't, they are screwing around and socializing. I had to pull Khan because of it and go back to paper-only Ray's arithmetic. Now they are using Khan in a limited way alongside classroom math instruction