My 4-year old and I enjoyed reading this book last night. Being a math person myself, it immediately became clear to me that this was going to be a fun way to learn and practice a bit of mathematics.
You start with 12 cookies divided between 2 kids and then more and more kids keep arriving and they have to divide the cookies up amongst everyone.
It wasn't very hard for my son, once I prompted him to get 12 blocks so he could pretend they were the cookies and divide them up appropriately. He first was trying to do it in his head and that was way too hard. He really seemed to enjoy making the different numbers of piles each time the doorbell rang!
It struck me during the reading of this book that perhaps I was "ruining" the book by trying to make it all educational instead of just relaxing and enjoying the story. But when the book was over, my son said "That was fun, can we do more math?"