Samuel announced yesterday that 7 times 2 is 14, and it would only take 6 more to get to 20. This may not seem that impressive, except that I have never taught him math except as it has come up in our daily life - you know, counting and whatnot. Most of it, he's figured out on his own because he thinks it's interesting. Somehow I don't think he'd be figuring out math concepts in his head for fun if he was drilled with worksheets.
We should probably work on his concept of time, though. Today I told him we had 10 more minutes at the pool, as he was getting blue and shivery. Then I gave him the 5-minute warning. "It's been 5 minutes already?" "Yes." "Those minutes are wimpy!"