# Lesson 13

Center Day 2 (optional)

## Warm-up: True or False: Two or False (10 minutes)

### Narrative

The purpose of this True or False is to elicit strategies and understandings students have for adding with multiples of 2 and 2 equal addends. These understandings help students deepen their understanding of the properties of operations, fluency within 20, and will be helpful practice as students develop foundations for multiplication.

### Launch

- Display one statement.
- “Give me a signal when you know whether the statement is true and can explain how you know.”
- 1 minute: quiet think time

### Activity

- Share and record answers and strategy.
- Repeat with each statement.

### Student Facing

Decide if each statement is true or false. Be prepared to explain your reasoning.

- \(2 + 2 + 2 + 2 = 4 + 4\)
- \(2 + 2 + 2 = 3 + 3\)
- \(2 + 2 + 2 + 2 + 2 + 2 = 5 + 5\)

### Student Response

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### Activity Synthesis

- “How can you explain your answer without finding the value of both sides?”

## Activity 1: Centers: Choice Time (40 minutes)

### Narrative

The purpose of this activity is for students to have another chance to practice skip-counting by 2, 5, and 10 and addition and subtraction within 1,000.

### Required Materials

Materials to Gather

### Required Preparation

Gather materials from:

- Write Numbers, Stage 4
- Target Numbers, Stages 6 and 7
- Five in a Row, Stages 7 and 8
- How Close, Stage 4

### Launch

- “Now you will choose from centers we have already learned.”
- Display the center choices in the student book.
- “Think about what you would like to do first.”
- 30 seconds: quiet think time

### Activity

- Invite students to work at the center of their choice.
- 15–20 minutes: center work time
- “Choose what you would like to do next.”
- 15–20 minutes: center work time
- If time allows, have students choose a third center to work on.

### Student Facing

Choose a center.

Write Numbers

Target Numbers

Five in a Row

How Close

### Activity Synthesis

- Invite 2-3 students to share their favorite method for adding and subtracting within 1,000.

## Lesson Synthesis

### Lesson Synthesis

“We have learned a lot about addition and subtraction this year. What are some important things we need to remember about addition and subtraction?”

Share and record responses.

“What questions do you have about addition and subtraction?”