So the teacher asks Johnny, "If I gave you two cats and then I gave you two more cats, how many cats would you have?"
Johnny says, "Five."
Teacher says, "No. Pay attention. If I gave you two cats and then I gave you two more, how many would you have?"
Johnny says, "Five."
She says, "Listen, if I gave you two apples and two more apples, how many would you have?"
Johnny says, "Four."
Teacher says, "Good. Now why do you get five when I ask you about the cats?"
Johnny says, "Cause I already have a cat."