A son calls up his mom from college to ask for some money. His mom says, " Sure, sweetie, I'll send you some money. You also left your economics book here last time you visited. Do you want that, too?"
The son prelies, " Yeah, sure, whatever."
So the mom goes to the post office to mail her son the money and the book. When she gets home, her husband asks her how much money she gave their son, to which she replied, " I sent him one check for $20 and one check for $1,000." Her husband freaks out! He yells," What were you thinking! That's $1,020."
His wife replied," Don't worry, I put the check for $20 on the cover of his economics book and the check for $1,000 in between the pages somewhere in chapter 15!"