# Lesson 14

Towers of 10

## Warm-up: What Do You Know About 10? (10 minutes)

### Narrative

The purpose of this What Do You Know About _____ is to invite students to share what they know and how they can represent the number 10.

### Launch

• Display the number.
• “What do you know about 10?”
• 1 minute: quiet think time

### Activity

• Record responses.
• “How could we show the number 10?”

### Student Facing

What do you know about 10?

### Activity Synthesis

• “Tell your partner 2 different ways that we can make 10.”

## Activity 1: Introduce What’s Behind My Back?, 10 Cubes (15 minutes)

### Narrative

The purpose of this activity is for students to learn stage 2 of the What’s Behind My Back center. Students snap a tower of 10 cubes into two parts and hide one part behind their back. Then, their partner determines how many connecting cubes are hidden. Students may use connecting cubes, 10-frames and counters, fingers, or drawings to figure out how many connecting cubes are hidden. As they choose a strategy, they will be making use of appropriate tools strategically (MP5). Monitor for students who:

• create another tower of 10 connecting cubes, snap it into two pieces to show the cubes that are showing and then count the rest of the cubes to determine how many cubes are hidden
• hold up the same number of fingers as the number of connecting cubes that are showing and count the number of fingers that are down to determine how many connecting cubes are hidden
• place counters on a 10-frame to represent the connecting cubes that are showing and count the empty squares to determine how many connecting cubes are hidden

### Required Materials

Materials to Gather

Materials to Copy

• What's Behind My Back Stage 2 Recording Sheet Kindergarten

### Required Preparation

• Each group of 2 need 20 connecting cubes.

### Launch

• Groups of 2
• Give each group of students 20 connecting cubes. Give each student a recording sheet and access to two-color counters and 10-frames.
• “We are going to learn a new way to play the What's Behind My Back? center.”
• “Work with your partner to make one tower with 10 connecting cubes.”
• 1 minute: partner work time
• “Choose who will go first. Snap the tower into two parts and hide one of the parts behind your back. Show your partner the other part.”
• 30 seconds: partner work time
• “Figure out how many cubes are hidden behind your partner’s back.”
• 2 minutes: independent work time
• “Draw or color the connecting cube tower to show the two parts that the tower snapped into. Work together to fill in an equation to show the total number of connecting cubes in the tower and the two parts that the tower snapped into.”
• 2 minutes: partner work time
• “Take turns snapping the tower of 10 cubes and hiding one part.”

### Activity

• 8 minutes: partner work time
• Monitor for students who use the methods outlined in the activity narrative.

### Activity Synthesis

• Select previously identified students to share.
• “How did making another tower of 10 cubes help you figure out how many cubes were hidden?”
• “How did putting counters on the 10-frame help you figure out how many cubes were hidden?”

## Activity 2: How Many Cubes Are Hidden? (10 minutes)

### Narrative

The purpose of this activity is for students to determine how many are needed to make 10 when added to a given number. This activity is presented as the same context as the first activity, except students are not shown the visual of the cubes. Because the context is connecting cubes, one natural way to determine how many cubes are hidden is to create and snap a tower of 10 cubes. Students may also use their fingers or put counters on a 10-frame. As they choose a strategy, they reason abstractly and quantitatively (MP2) and they may choose to use appropriate tools strategically (MP5).

MLR8 Discussion Supports. Invite students to say each equation aloud. Listen for and clarify any questions about the equations.
Action and Expression: Internalize Executive Functions. Invite students to plan a strategy, including what drawings, numbers, words, or objects they will use to determine how many cubes Han is hiding.
Supports accessibility for: Conceptual Processing, Organization

### Required Materials

Materials to Gather

### Launch

• Groups of 2
• “Show your thinking using drawings, numbers, words, or objects.”

### Activity

• 3 minutes: independent work time
• 2 minutes: partner work time
• Monitor for students who build a tower and snap off 4 cubes to figure out how many cubes are missing.
• “Fill in an equation to show Han’s cubes.”
• 1 minute: partner work time

### Student Facing

Han had a tower of 10 cubes.

He snapped it into 2 parts and hid 1 part behind his back.

He showed his partner 4 cubes.

How many cubes is Han hiding behind his back?

$$10 = \underline{\hspace{1 cm}} + \underline{\hspace{1 cm}}$$

### Student Response

If students are unsure of how to find the missing part, consider asking:

• “Can you use cubes to show what happened in the story?”
• “How can you use the cubes to help you figure out how many cubes Han was hiding behind his back?”

### Activity Synthesis

• Invite students who built towers of connecting cubes to show how they figured out how many cubes were hidden.
• Display a 10-frame with 4 red counters and 6 yellow counters. Display a tower of 10 connecting cubes broken into 4 and 6:
• “How is making 10 with connecting cubes the same as using a 10-frame?” (I get the same combinations of numbers to make 10. 4 connecting cubes and 6 connecting cubes make 10 just like with counters.)

## Activity 3: Centers: Choice Time (20 minutes)

### Narrative

The purpose of this activity is for students to choose from activities that offer practice with counting, adding, composing, and decomposing numbers.

Students choose from any stage of previously introduced centers.

• What’s Behind My Back?
• Math Fingers
• Shake and Spill
• Counting Collections

### Required Materials

Materials to Gather

### Required Preparation

• Gather materials from:
• What's Behind My Back, Stages 1 and 2
• Math Fingers, Stages 1-4
• Shake and Spill, Stages 1-3
• Counting Collections, Stage 1
• Roll and Add, Stages 1 and 2

### Launch

• “Today we are going to choose from centers we have already learned. You can also continue playing What’s Behind my Back?”
• 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.
• 8 minutes: center work time
• “Choose what you would like to do next.”
• 8 minutes: center work time

### Student Facing

Choose a center.

What’s Behind My Back?

Math Fingers

Shake and Spill

Counting Collections

### Activity Synthesis

• Display a tower of 10 cubes, snapped into 9 cubes and 1 cube.
• “What are the parts that make 10 that Elena found?” (9 and 1)
• “What equation can Elena write?” ($$10 = 9 + 1$$)

## Lesson Synthesis

### Lesson Synthesis

Display a 10-frame with 4 red and 6 yellow counters.

Display 10 connecting cubes snapped into towers of 1 and 9.

Display 10 fingers.

Write $$10 = 7 + 3$$.

“We have looked at lots of ways to make 10: 10-frames, fingers, expressions and equations, and towers of connecting cubes.”

“What is your favorite way to make 10? Why is it your favorite?”

## Student Section Summary

### Student Facing

In this section, we found many different ways to make 10.

We used a 10-frame and our fingers to show numbers and figure out how many more are needed to make 10.

There are 4 counters.
We need 6 more counters to make 10.

There are 9 fingers.
We need to put up 1 more finger to make 10.

We used equations to show different ways to make 10.

$$10 = 4 + 6$$

$$10 = 9 + 1$$