We had some friends over to dinner on Saturday night. In an effort to keep DS4 occupied for at least a little bit of time, I asked him to make an 8x8 square on his Geoboard and figure out what the area is. I hardly noticed the quiet as he sat their calculating. After about 5 minutes he triumphantly announced "64!". I looked down to see the paper on which he had carefully written the following: 816243240485664. Evidently he hasn't learned the use of the comma yet.