1 - Suppose you need to measure exactly 1 cup of water. All you have are two measuring cups. The smaller measuring cup holds 3 cups and the larger holds 5 cups. How can you use thee two cups to measure exactly 1 cup of water?
2 - Place two fingers at the end of a yardstick. Slowly move the fingers toward each other. As you'll discover, your fingers will always meet in the middle of the yardstick. Now place both fingers in the middle of the yardstick and slowly try moving the two fingers out to the opposite ends. This time you'll find that one finger remains in the middle while the other finger moves toward the end. How can you explain this action?
2 - Place two fingers at the end of a yardstick. Slowly move the fingers toward each other. As you'll discover, your fingers will always meet in the middle of the yardstick. Now place both fingers in the middle of the yardstick and slowly try moving the two fingers out to the opposite ends. This time you'll find that one finger remains in the middle while the other finger moves toward the end. How can you explain this action?