This reminded me of a question my daughter asked me. She was confused by the fact that the tooth fairy (me) had left her $3 the first time and $1 the second time. I had to tell her that the tooth fairy has to divide the money equally among all the children who leave a tooth under their pillow that night. That is, if there are many children to whom she has to distribute money that night, that means each one will get less, but if on the other hand there are only a few children, then she will give them more money. She seemed satisfied with the answer.