Lesson 14
Towers of 10
Lesson Purpose
Lesson Narrative
In previous lessons, students composed and decomposed 10 in multiple ways and found the number that makes 10 when added to a given number. In this lesson, students determine how many cubes are hidden when a tower of 10 connecting cubes is broken into 2 parts and only 1 part is visible. Determining how many more are needed to make 10 is more challenging with connecting cubes than with a 10frame or fingers because students cannot use the structure of the 10frame or fingers and simply count the empty squares or the fingers that are down. The goal of the lesson synthesis is for students to reflect on the different tools they have used to compose and decompose 10.
 Action and Expression
 MLR8
Activity 1: Introduce What’s Behind My Back?, 10 Cubes
Learning Goals
Teacher Facing
 Find the number that makes 10 when added to a given number.
Student Facing
 Let’s figure out how many cubes are hidden.
Required Materials
Materials to Gather
Materials to Copy
 What's Behind My Back Stage 2 Recording Sheet Kindergarten
Required Preparation
Activity 1:
 Each group of 2 need 20 connecting cubes.
Activity 3:
 Gather materials from:
 What's Behind My Back, Stages 1 and 2
 Math Fingers, Stages 14
 Shake and Spill, Stages 13
 Counting Collections, Stage 1
 Roll and Add, Stages 1 and 2
Lesson Timeline
Warmup  10 min 
Activity 1  15 min 
Activity 2  10 min 
Activity 3  20 min 
Lesson Synthesis  10 min 
Cooldown  0 min 
Teacher Reflection Questions
Print Formatted Materials
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Additional Resources
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