Little Johnny is always being teased by the other neighborhood boys for being stupid. Their favorite joke is to offer Jonny his choice between a nickel and a dime — Little Johnny always takes the nickel.
One day, after Johnny takes the nickel, a neighbor takes him aside and says, “Johnny, those are making fun of you. Don’t you know that a dime is worth more than a nickel, even though the nickel’s bigger?”
“Johnny grins and says, “Well, if I took the dime, they’d stop doing it, and so far I have made $20!”