Jack is a math whiz

Just now, as he was sitting on the potty while I folded laundry nearby, Jack asked "Is twenty twenties something around four hundred?" I told him that it is exactly four hundred, and reminded him that squaring something is multiplying it by itself, just like twenty twenties, so we can say that twenty squared is four hundred. Math comes easily to him, but names take a long time to take root in his mind. I wonder how long it will be before he remembers the concept of squaring.