In the lessons leading up to this one, students learned about arithmetic and geometric sequences, their links to linear and exponential functions studied in previous courses, and how to define sequences recursively, using function notation. In this activity, students are introduced to the Information Gap routine, which offers them the opportunity to bring together what they have learned to solve a problem involving sequences.

In the Warm-up activity, students are walked through the process of asking for information needed to solve a problem. Then, students practice the Info Gap routine for themselves in small groups. To obtain all the necessary information, students need to persevere in asking questions (MP1) and to communicate precisely (MP6).

Math Community
Today, students use sticky notes to document actions in the “Doing Math” sections of the Math Community Chart that they see or hear throughout the lesson. During the Lesson Synthesis, students share what they noticed, and then they suggest additions for the chart as part of the Cool-down. The work today continues to build a foundation for developing math community norms in a later exercise and is the start of students identifying strengths in the actions of their peers.