I agree it's not a good excuse to hold him back. He can still fill in the gaps while learning the new material if necessary. He's learning 2nd grade math now so he's already ahead of the other kids who will be chosen to get into this new program. Also,once or twice a week being pulled out of regular class is not enough for him. It's not much different than what he's doing now. He needs a regular/daily math class that can challenge him and push him.

I will talk to the principal and push for the 3rd grade math.