Sadly, our DS6 still enjoys those. 1 + 1 still equals 11, and so forth. He'll offer up these jokes quite often, which is "so much fun". But to our knowledge, he does that kind of stuff with us and has never done it with a teacher. I really don't think he did it when he was assessed, either.

Just in case though, I agree with Mana that I'd wait to test until you have a specific reason to do so.