Luis, dressed as a magician, demonstrates addition by conjuring up the correct numeral when David and Maria arrive. As each person leaves, Luis switches the numerals to present subtraction.
Mr. Hooper, Luis, Maria, David and Bob all throw a small amount of litter on the ground, adding to the street's filth. When a voice (Jerry Nelson asks "Who made this mess?" each one of them denies that it was them, saying they only dropped a small amount of garbage on the street. Soon, however, they realize that they each contributed to the mess in one way or another and pick up what they dropped. The voice then tells them to put the trash in a trash can instead of on the ground.