Angles are ever present on an analog clock. In this lesson, students investigate and solve problems about the angles formed by a clock’s hour and minute hands. Students reason about the number of degrees between the two hands or the number of degrees the minute hand has turned over some specified time. To do so, students rely on their understanding of fractional parts (for example, a round clock can be divided into both 12 equal parts and 60 equal parts), their ability to tell time and elapsed time, and their knowledge of angle types and measurements.

How did students’ understandings about time—how to tell time and find elapsed time—help their work with angles on the clock?