Middle child to youngest: Go wash your hands.
Youngest: Why?
Middle: Because you just went to the bathroom and I didn't hear the water running.
Youngest: But why do I have to do it every time?
Me: Because your hands are dirty every time.
Middle: Yes, you should wash your hands 35 times a day like I do.
Oldest to me: Pfft. That's a lie. You know how I know he's lying about that 35 times thing?
Me: How?
Oldest: Because it's an odd number.