A kid called his mom from college and asked her for some money, because he ran out.
Mom said, "Sure, sweetie. I'll send you some money. You also left your Calculus book here when you visited two weeks ago. Do you want me to send that up too?"
"Uh, oh yeah, OK," responded the kid.
So Mom wrapped the book along with the checks up in a package, kissed Dad goodbye, and went to the post office to mail the money and the book.
When she gets back, Dad asked, "Well how much did you give the boy this time?
Mom said, "Oh, I wrote two checks, one for $20, and the other for $1000"
"That's $1020!!!" yelled Dad, "Are you crazy???"
"Don't worry honey," Mom said, as she kissed Dad on the on top of his bald head, "I taped the $20 check to the cover of his book, but I put the $1000 one somewhere between the pages in Chapter 19!"