Lesson 11
Make Them the Same
Warmup: Notice and Wonder: Cube Towers (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.
 Revoice and emphasize “more than” and “fewer than.”
Student Facing
What do you notice?
What do you wonder?
Student Response
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Activity Synthesis
 “We will use connecting cube towers and think about how to make them have the same number of cubes.”
Activity 1: Cube Towers (15 minutes)
Narrative
The purpose of this activity is for students to find ways to make two quantities the same. Students may use connecting cubes to represent and solve the problems, if they choose. Students are more likely to add cubes to make the towers have an equal number of cubes, but some students may take cubes away. Students record how they solved each problem in a way that makes sense to them. During the synthesis, the teacher records equations that match the way students solved the problem to build on work in previous sections.
Required Materials
Materials to Gather
Required Preparation
 Create a tower of 9 blue connecting cubes and a tower of 5 red connecting cubes.
 Each group of 2 needs 4 towers of 10 connecting cubes.
Launch
 Groups of 2
 Give each group four towers of ten connecting cubes.
 Display a tower of nine blue connecting cubes and a tower of five red connecting cubes, or the image in the student book.
 “Diego and Jada are building connecting cube towers. How can Diego and Jada make their towers have the same number of cubes? Remember, you are not sharing the answer with your partner; you are sharing your method for solving the problem.” (They can add some cubes to the red tower or take some off the blue tower.)
 1 minute: quiet think time
 1 minute: partner discussion
 Share responses.
Activity
 “You are going to record your thinking for this problem and solve two more problems about making Diego and Jada’s connecting cube towers have the same number of cubes. You may use the connecting cubes to help if you choose.”
 5 minutes: independent work time
 Monitor for students who have clear representations for problem 3 showing:
 adding cubes to Diego’s tower
 counting up the difference between Diego’s tower to Jada’s tower
 taking cubes from Jada’s tower
 counting back the difference between Jada’s tower to Diego’s tower
Student Facing
How can Diego and Jada make their towers have the same number of cubes?
Show your thinking using drawings, numbers, or words.
Student Response
For access, consult one of our IM Certified Partners.
Activity Synthesis
 Invite previously identified students to share.
 “What do you notice about all these methods?” (They all got the same answer, even if they added cubes or took cubes off.)
 “What equation would you write to match the story problem? How does your equation show how you solved the story problem?” (\(3 + 7 = 10\), because I added 7 cubes onto Diego’s tower to make them the same. \(10  3 = 7\), because I broke off from Jada’s tower and counted what I broke off.)
Activity 2: Cube Tower Problems (20 minutes)
Narrative
The purpose of this activity is for students to solve Compare, Difference Unknown story problems in the context of connecting cube towers. Students solve comparison problems with given constraints that encourage students to add or break apart cubes to make towers with the same number of cubes. As students explain their thinking during the synthesis, record both addition and subtraction equations. When students answer the question, "How do you know?" they are beginning to explain their reasoning and construct viable arguments (MP3).
Advances: Listening, Speaking
Supports accessibility for: VisualSpatial Processing, Conceptual Processing
Required Materials
Materials to Gather
Required Preparation
 Gather 1 red tower of 8 connecting cubes, 1 yellow tower of 3 connecting cubes, and a handful of yellow cubes.
 Each group of 2 needs 4 towers of 10 connecting cubes.
Launch
 Groups of 2
 Give each group four towers of ten connecting cubes.
 Display one red tower of eight connecting cubes, one yellow tower of three connecting cubes, and the handful of yellow connecting cubes.
 “I have two towers and I need to make them the same number of cubes. But I only have these yellow cubes. How can I make them the same?”
 1 minute: quiet think time
 1 minute: partner discussion
 Share and record responses.
Activity
 “Lin is working to make the number of cubes in each of her towers the same. Each problem will tell you what cubes she has to work with. Record your thinking for each tower.”
 8 minutes: independent work time
 “Share your thinking with your partner.”
 4 minutes: partner discussion
 Monitor for a student who solved the problem with 7 yellow cubes and 3 red cubes by adding 4 red cubes or drawing 4 more red cubes.
Student Facing

Lin has only blue cubes.
How can Lin make the towers have the same number of cubes?
Show your thinking using drawings, numbers, or words. 
Lin has no more yellow cubes.
How can she make the towers have the same number of cubes?
Show your thinking using drawings, numbers, or words. 
Lin is making 2 cube towers.
The red tower has 6 cubes.
The blue tower has 9 cubes.
She has no more red cubes.
How can she make the towers have the same number of cubes?
Show your thinking using drawings, numbers, or words. 
Lin is making 2 cube towers.
The yellow tower has 7 cubes.
The red tower has 3 cubes.
She only has red cubes.
How can she make the towers have the same number of cubes?
Show your thinking using drawings, numbers, or words.
If you have time: Write your own problem about 2 cube towers.
Trade problems with a partner and solve.
Student Response
For access, consult one of our IM Certified Partners.
Activity Synthesis
 Display selected student work.
 “How did they solve the problem?” (She added 4 red cubes.)
 “What equation matches how they solved? How do you know?” (\(3 + 4 = 7\) because Lin started with 3 red cubes and she added 4 cubes to make it the same.)
 “Which number in the equation represents the answer to the problem?” (4 because that is how many cubes Lin added.)
 Put a box around the 4.
Lesson Synthesis
Lesson Synthesis
Display one red tower of eight connecting cubes, one yellow tower of three connecting cubes, and a handful of yellow connecting cubes.
“Today we made towers have the same number of cubes by adding more cubes to the smaller tower or taking cubes from the larger tower. How does adding more cubes relate to addition?” (I can add cubes to the tower with fewer cubes to make them the same.)
Cooldown: Make Them the Same (5 minutes)
CoolDown
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