Mathematics of Sleep

So, the kids slept yesterday in the car for two hours. Wonderful, restorative.

And then they went to bed at their usual (new) time (after the time change, it's now 7:30-8 pm).

They usually sleep about 11 hours, meaning wakeup around 7 am.

But today it was 5 am.

They subtracted the two hour nap.

I didn't know they knew math; we can barely count past 15 (in order).