Silly Subtraction

I was in the bathroom with Josiah this morning and this is the conversation we had:

JOEY: I will go down the drain and then you will only have two kids.
ME: I would miss you.
JOEY: Then if Livia goes down the drain you will only have one kid.
ME: Uh huh.
JOEY: If Hope goes down the drain then there would be no kids.

I guess we can assume he has learned how to subtract.