Lesson 15

The purpose of this lesson is for students to connect Compare problems with unknowns in all positions to tape diagrams.

In this lesson, students continue to make sense of tape diagrams as they connect them to story problems. The story problems in this lesson include Compare problems with an unknown difference, an unknown larger number, or an unknown smaller number. Because these problem types are familiar from grade 1, students also begin to work with numbers within 100 in this lesson. This gives students an opportunity to notice how the tape diagram can be used to quickly visualize story problems with larger quantities. Students use tape diagrams to make sense of Compare problems. When students connect situations, tape diagrams, and equations, they deepen their understanding of the problem type and develop strategies they can use to make sense of and persevere in solving these problems in future lessons (MP1, MP2).

• Create a set of cards from the blackline master for each group of 2.

As students worked in their small groups today, whose ideas were heard, valued, and accepted? How can you adjust the group structure in future lessons to ensure each student’s ideas are a part of the collective learning?