In "Democracy", Charlie tries to convince Oswald Kitner to join CalSci's academic program by giving him the following problem: "Suppose there are five couples at a party. People shake hands, but no one shakes hands with the person they came with. At one point, one man asks the nine others how many hands they shook, and gets nine different answers. How many hands did the man himself shake?" This activity explores this problem, and lets students discover an inductive way of solving it.
Before the Activity
Download the attached PDF and look over the Teacher Page.
During the Activity
Discuss the materials from the Student Page with your class.
After the Activity
Encourage students to explore Web sites and questions from the Extensions Page.