The print out doesn't say which test he took. They did mention when I asked why the score went down that he took the first one in a room by himself and the second with his classmates, so maybe they were indicating distraction may have contributed to the drop? If he hit the ceiling on the first test there is a good chance they gave him the higher test the second time.
I don't think summer slump is likely for DS, we started homeschool for K last year and went straight through summer right up until the week before he started 1st grade at his new school. We were halfway through 3rd grade curriculum, so I was just wondering if his scores are consistent with what we did in homeschool. I'm not much of a math teacher and I always worried I wasn't doing a very good job of it.
They have started him on Khan academy at the 3rd grade level, but he's getting a pull out for some sort of early calculus program as well. I'm assuming the Khan academy is to cover some gaps while the calculus is to teach him something fun and interesting (fun and interesting for him anyway).
