In "Convergence," Charlie talks about calendars and refers to them as "mathematical tools." Your students have undoubtedly noticed patterns in the days of the week from year to year when certain holidays are celebrated, or when their birthdays fall during the week. This activity is designed to have students think about the many patterns that arise when you study how the day of the week for a particular date (say October 11) changes from one year to the next.
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.