# Lesson 18

Patterns in Addition

## Warm-up: How Many Do You See: More Double 10-frames (10 minutes)

### Narrative

### Launch

- Groups of 2
- “How many do you see? How do you see them?”
- Flash the image.
- 30 seconds: quiet think time

### Activity

- Display the image.
- “Discuss your thinking with your partner.”
- 1 minute: partner discussion
- Record responses.
- Repeat for each image.

### Student Facing

How many do you see?

How do you see them?

### Student Response

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### Activity Synthesis

- “What do these images have in common?” (You can take some dots from one 10-frame and add them to the other. None of the 10-frames are full.)
- “The first image shows \(9 + 5\), but if we share one yellow with the top 10-frame we could write \(10 + 4\).”
- Write \(9 + 5 = 10 + 4\).
- “What expressions could we write for the second image?” (\(3 + 9 = 2 + 10\))

## Activity 1: Expression Match (10 minutes)

### Narrative

The purpose of this activity is for students to use what they know about making a ten to identify which addition expressions are equivalent to \(10 + n\) expressions. Students should have access to double 10-frames and connecting cubes or two-color counters.

The Compare Stage 2 Addition Cards will be used again in a later lesson.

### Required Materials

Materials to Gather

Materials to Copy

- Compare Stage 2 Addition Cards to 20

### Required Preparation

- Create a set of Compare Stage 2 Addition Cards to 20 from the blackline master for each group of 3.

### Launch

- Groups of 3
- Give each group a set of cards and access to double 10-frames and connecting cubes or two-color counters.

### Activity

- Read the task statement.
- 8 minutes: small-group work

### Student Facing

- Take out all the expression cards that have the number 10.
- Mix up the rest of the cards.
- Pick a card.
- Place the card under the expression with 10 that it is equal to.

### Student Response

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### Activity Synthesis

- “We are going to create a poster and do a Gallery Walk.”

## Activity 2: Compare and Connect: Gallery Walk (15 minutes)

### Narrative

The purpose of this activity is for students to create a poster to show all the expressions equivalent to their assigned \(10 + n\) expression. Before the activity, assign each group an expression for which they will make a poster. Then, students get into new groups of three and each group visits three posters. Students consider what patterns they notice between the expressions on the poster. Students may notice there is a relationship between the addends of equivalent expressions. For example, when one addend decreases by 1, the other addend in the sum increases by 1 (MP7).

This activity uses *MLR7 Compare and Connect. Advances: Representing, Conversing*

*Action and Expression: Develop Expression and Communication.*Provide students with alternatives to writing their observations on paper: students can share their observations verbally, or through drawings.

*Supports accessibility for: Language, Conceptual Processing*

### Required Materials

Materials to Gather

### Launch

- Groups of 3
- Give each group tools for creating a visual display.
- Assign each group an expression.

### Activity

**MLR7 Compare and Connect**

- “Create a visual display that shows the expressions equal to the expression with 10 I assigned you.”
- 3 minutes: small group work
- 7 minutes: gallery walk
- During the gallery walk, consider asking:
- “What do you notice about the expressions on the poster?”
- “What patterns do you notice?”
- “Are the patterns the same across all of the posters?”

### Activity Synthesis

- Display posters for \(10 + 1\), \(10 + 3\), and \(10 + 5\).
- “What patterns did you notice as you went from poster to poster?” (I saw that there was an expression with 9 on every poster. For example, \(10 + 3\) is equivalent to \(9 + 4\). This is because I can take 1 from the 4 and give it to the 9.) To amplify student language and illustrate connections, follow along and point to the relevant parts of the displays as students speak.
- Record responses as equations (for example, \(10 + 3 = 9 + 4\)).
- Record \(10 + 3 = 9 + 4\). “Is the same pattern on other posters?” (Yes, it happened on \(10 + 2\). If I have \(9 + 3\), I can take one from the 3 and give it to the 9. Then I have \(10 + 1\).)

## Activity 3: Centers: Choice Time (15 minutes)

### Narrative

The purpose of this activity is for students to choose from activities that offer practice adding and subtracting within 10. Students choose from any stage of previously introduced centers.

- Shake and Spill
- Compare
- Number Puzzles

### Required Materials

Materials to Gather

### Required Preparation

- Gather materials from previous centers:
- Shake and Spill, Stages 3–5
- Compare, Stage 1
- Number Puzzles, Stages 1 and 2

### Launch

- Groups of 2
- “Now you are going to choose from centers we have already learned.”
- Display the center choices in the student book.
- “Think about what you would like to do.”
- 30 seconds: quiet think time

### Activity

- Invite students to work at the center of their choice.
- 10 minutes: center work time

### Student Facing

Choose a center.

Shake and Spill

Compare

Number Puzzles

### Activity Synthesis

- Display nine red counters and cover five yellow counters with a cup.
- “We are playing with 14 counters. How many yellow counters are under the cup? How do you know?”

## Lesson Synthesis

### Lesson Synthesis

Display a double 10-frame with eight counters on the top frame and four on the bottom, and \(8 + 4 = 10 + 3\).

“Today we matched addition expressions to equivalent expressions with a 10. Is this equation true or false? How do you know?” (It’s false, because if I move two counters to the top 10-frame then it shows \(10 + 2\).)

## Cool-down: Unit 3, Section C Checkpoint (0 minutes)

### Cool-Down

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