# Lesson 15

Center Day 3 (optional)

### Lesson Purpose

The purpose of this lesson is for students to interpret diagrams, solve story problems, and add and subtract within 100.

### Lesson Narrative

This lesson is optional because it is an opportunity for extra practice interpreting diagrams and adding and subtracting within 100 that not all classes may need. In the first activity, students learn stage 5 of the Math Stories center, which was last introduced in grade 1. In this new stage, called Tape Diagrams, students interpret tape diagrams and create their own story problems to solve. Then, students choose a center based on what they need to practice. Students may continue to choose stages that provide additional practice adding and subtracting two-digit numbers or may choose the stages that provide fluency practice with addition and subtraction within 20.

As needed, revisit and reinforce the structures and norms for centers that were established in previous lessons.

### Learning Goals

Teacher Facing

• Add and subtract within 100.
• Interpret diagrams.
• Solve one-step story problems.

### Student Facing

• Let’s use diagrams to make our own story problems and solve them.

### Required Materials

Materials to Gather

Materials to Copy

• Math Stories Stage 5 Tape Diagrams
• Math Stories Stage 5 Recording Sheet

### Required Preparation

Activity 1:

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

Activity 2:

Gather materials from:

• Target Numbers, Stages 4 and 5
• Capture Squares, Stages 3 and 4
• Five in a Row, Stage 6

### Lesson Timeline

 Warm-up 10 min Activity 1 20 min Activity 2 20 min Lesson Synthesis 10 min

### Teacher Reflection Questions

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

### Print Formatted Materials

 Student Task Statements pdf docx Lesson Cover Page pdf docx Teacher Guide Log In Teacher Presentation Materials pdf docx Blackline Masters zip