Here is one from the archives.
Nearly a year ago, Griffin was seven years old and I was doing some thinking about the number course I teach for future elementary teachers. I decided to see how Griffin was thinking about place value.
Me: How many tens are in 32?
Griffin (seven years old at the time): Three, and then two leftover.
Me: How do you know that?
G: Thirty—that’s three tens, and then the zero means no ones.
Me: How many tens in 268?
G: [long thoughtful pause] Twenty-six, and then there would be 8 left over.
Me: What would you say to someone who thought there were six tens in 268?
G: I’d say there are 20 more than that.
That’s my boy.