base ten numbers and discipline

I give you a recent conversation between J and my mother (Nana).
Guess who hasn't been on his best behavior lately?

J: Nana, will you come to my birthday party?

Nana: Sure J, how old are you going to be?

J (smirking): Seven.

Nana: Seven?! You're not seven. How old are you now?

J (more smirking) Two.

Nana: Oh, come on J. You are Three. What comes after Three?

J: Time Out