And his response was "That's easy! Can you write it on the board?"
So I did.
And he promptly, and correctly, solved it.
And I was floored. I went to ask his math teacher, with whom he does an individualized computer math program every week. This seven-year old boy is on a fourth grade math level, and can do 5-digit multiplication, as well as being the best math student in the school. If only I had known! I would have had him finish his math book a long time ago and given him something much more stimulating than double digit addition to be practicing!! This is why assessments are a good thing...