Happy Halloween

Why is it that my estimation of the number of kids is hugely off each year?

The first year we planned for 80, since we had no idea and knew we were on a busy dead end street and ended up having 40 kids.

Last year, I planned for 60, since I knew there were a few new kids in the neighbourhood and we had 30.

This year I made 40 bags, and bought an extra box of chocolate bars, a bag of suckers and 2 bags of gum, making sure to get the things we liked since they wouldn't be for the kids anyway. And of course we end up with 70 kids!

Needless to say, there isn't much left over!