There was a little boy named Johnny who used to hang out at the local corner market. The owner didn't know what Johnny's problem was, but the boys would constantly tease him. They would always comment that he was two bricks shy of a load, or two pickles short of a barrel. To prove it, sometimes they would offer Johnny his choice between a nickel (5 cents) and a dime (10 cents) and John would always take the nickel ... they said, because it was bigger.
One day after Little Johnny grabbed the nickel, the store owner took him aside and said "Johnny, those boys are making fun of you. They think you don't know the dime is worth more than the nickel. Are you grabbing the nickel because it's bigger, or what?"
Slowly, Little Johnny turned toward the store owner and a big grin appeared on his face and he said, "Well, if I took the dime, they'd stop doing it, and so far I have saved $20!"
Little Johnny's preschool class went on a field trip to the fire station. The firefighter giving the presentation held up a smoke detector and asked the class: "Does anyone know what this is?"
Little Johnny's hand shot up and the firefighter called on him.
Little Johnny replied: "That's how Mommy knows supper is ready!"