Lesson 23

The purpose of this lesson is for students to use the four operations to solve problems involving multi-digit numbers. Students also use the standard algorithm for addition and subtraction to solve problems. For each problem, they assess the reasonableness of their responses.

In the preceding lessons, students interpret situations and solve them using a variety of reasoning strategies. The computations focus mostly on multiplication and division, and the numbers are mainly two and three digits long.

In this lesson, students continue to engage in problem solving—this time in the context of finding distances. Students now use the four operations and work with numbers up to five digits. In the next lesson, they will work with numbers up to 1 million.

As you finish up this unit, reflect on the norms and activities that have supported each student in learning math. How have you seen each student grow as a young mathematician throughout this work? How have you seen yourself grow as a teacher? What will you continue to do and what will you improve on in Unit 7?