# Lesson 9

Addition With a Ten

## Warm-up: Notice and Wonder: Teen Numbers (10 minutes)

### Narrative

### Launch

- Groups of 2
- Display the image.
- “What do you notice? What do you wonder?”
- 1 minute: quiet think time

### Activity

- “Discuss your thinking with your partner.”
- 1 minute: partner discussion
- Share and record responses.

### Student Facing

What do you notice?

What do you wonder?

### Student Response

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### Activity Synthesis

- “How could you figure out how many objects there are in each image?” (I saw that one whole 10-frame was filled, so I knew that was 10. Then I counted on. I saw that the connecting cubes were in a tower of 10 and then there were some more left over. I could count all the objects in the image.)

## Activity 1: Make It: Teen Numbers and 10-Frames (20 minutes)

### Narrative

The purpose of this activity is for students to continue to explore teen numbers as 1 ten and some ones, using a new version of a familiar tool, the double 10-frame. Students choose a teen number and build it. As they build teen numbers, students should notice that every teen number has a completed 10-frame. or 1 ten, in common. This further solidifies student understanding that all teen numbers have 1 ten. Some students may build the teen number, counter by counter, each time. These students are still developing an understanding of 10 ones as 1 ten. Some students may realize that one of the 10-frames is always completely filled and only change the ones. When students notice the relationship between teen numbers and the 10 + n pattern, they look for and make use of structure (MP7). Students who leave one 10-frame full and change the counters in the other 10-frame are observing regularity in how the teen numbers are formed (MP8).

Double 10-Frames are provided as a blackline master. Students will continue to use these throughout the year. Consider copying them on cardstock or laminating them and keeping them organized to be used repeatedly.

*MLR8 Discussion Supports.*Invite students to begin partner interactions by repeating the question, “How can we use a ten-frame and counters to build this number?” This gives both students an opportunity to produce language.

*Advances: Conversing, Speaking*

### Required Materials

Materials to Gather

Materials to Copy

- Double 10-Frame - Standard
- Number Cards 11-20

### Required Preparation

- Create a set of Number Cards (11-20) from the blackline master for each group of 2.

### Launch

- Groups of 2
- Give each group a set of cards, a double 10-frame, and access to at least 20 connecting cubes or two-color counters.
- “We’re going to use our double 10-frames to build teen numbers today. Let's do one together.”
- Choose a card.
- “What number is on my card? Let's build that number on the double 10-frame.”
- Demonstrate building the teen number.
- “Now we write an equation to show how we built the number.”
- Write an equation such as 10 + 4 = 14.

### Activity

- “Now you will build more teen numbers with your partner. Make sure you both agree on how to build the number and what equation to write.”
- 10 minutes: partner work time
- Monitor for students who:
- build a new ten each time
- count the 10 each time
- change the ones only

### Student Facing

Use your 10-frames to build teen numbers.

Write an equation that matches the teen number.

teen number | equation |
---|---|

If you have time, write another equation for each of the teen numbers.

### Student Response

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### Advancing Student Thinking

If students remove all counters from the 10-frames and build a new ten for each teen number, consider asking:

- “Can you explain how you built this number?”
- “Can you keep some of the counters here to help you build your next number?”

### Activity Synthesis

- “When you were building these numbers, what part of the equation was the same? What part was different?” (There was always 10 in each equation. I was adding each time. The total changed and was always a teen number. The number I was adding to 10 changed.)

## Activity 2: Equations With a Ten (15 minutes)

### Narrative

*Representation: Internalize Comprehension.*Activate background knowledge. Begin by asking, “Do these problems remind anyone of something we have seen or done before?”

*Supports accessibility for: Conceptual Processing, Attention*

### Required Materials

Materials to Gather

### Launch

- Groups of 2
- Give students access to double 10-frames and connecting cubes or two-color counters.

### Activity

- Read the task statement.
- 6 minutes: independent work time
- 4 minutes: partner discussion

### Student Facing

Find the number that makes each equation true.

Show your thinking using drawings, numbers, or words.

- \(14 = 10 + \boxed{\phantom{\frac{aaai}{aaai}}}\)
- \(10 + 5 = \boxed{\phantom{\frac{aaai}{aaai}}}\)
- \(16 = \boxed{\phantom{\frac{aaai}{aaai}}} + 6\)
- \(10 + \boxed{\phantom{\frac{aaai}{aaai}}} = 12\)
- \(\boxed{\phantom{\frac{aaai}{aaai}}}+ 3 = 13\)
- \(13 = \boxed{\phantom{\frac{aaai}{aaai}}} + 10\)

### Student Response

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### Activity Synthesis

- “How are the last two problems related?” (They both show that 13 is the same as 10 and 3. 13 is the sum but they have different missing values.)

## Lesson Synthesis

### Lesson Synthesis

Display 18 using double 10-frames.

“Today we showed teen numbers on double 10-frames and wrote equations to match. What equations can you write to represent this number?” (\(10 + 8 = 18\), \(18 = 8 + 10\))

“How do these equations help you understand teen numbers?” (Teen numbers can be made up of a ten and some number of ones. This can be represented as 10 plus something.)

## Cool-down: Missing Number (5 minutes)

### Cool-Down

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