Lesson 10
Complete Equations
Warmup: What do you know about 15? (10 minutes)
Narrative
Launch
 Display the number.
 “What do you know about 15?”
 1 minute: quiet think time
Activity
 Record responses.
Student Facing
What do you know about 15?
Student Response
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Activity Synthesis
 “We have shown numbers 11–19 in lots of different ways. We have used fingers, 10frames, written numbers, and expressions. In the next activity we will show these numbers as equations.”
Activity 1: What Is Missing? (10 minutes)
Narrative
The purpose of this activity is for students to fill in equations to represent decompositions of numbers 11–19 on 10frames. Students fill in either the total or the two parts missing from the equations. When students relate the parts of the 10frame representations and the equations they reason abstractly and quantitatively (MP2).
Advances: Conversing
Launch
 Groups of 2
 “Use the dots to find the numbers that make each equation true.”
Activity
 2 minutes: independent work time
 3 minutes: partner work time
Student Facing
\( 10 + 8 = \underline{\hspace{1.4 cm}}\)
\( 10 + 3 = \underline{\hspace{1.4 cm}}\)
\( 10 + 4 = \underline{\hspace{1.4 cm}}\)
\(\underline{\hspace{1.4 cm}} + \underline{\hspace{1.4 cm}} = 16\)
\(\underline{\hspace{1.4 cm}} + \underline{\hspace{1.4 cm}} = 19\)
\(\underline{\hspace{1.4 cm}} + \underline{\hspace{1.4 cm}} = 12\)
Student Response
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Activity Synthesis
 Display the image with 18 dots and the matching equation.
 “How did you figure out what was missing?” (I counted the dots to find out how many there are altogether.)
 Display the image with 16 dots and the matching equation.
 “How did you figure out what was missing?” (I looked for the two parts. There are 10 on the 10frame and then there are 6 more.)
 “Sometimes the total number of dots was missing. Sometimes the two parts were missing.”
Activity 2: Make the Equations True (10 minutes)
Narrative
The purpose of this activity is for students to complete equations to represent numbers 11–19. Students may know that 17 is 10 and 7 because of repeated practice in this unit. Students may need to use objects or drawings to represent each number and then fill in an equation. While there are many possible equations to represent each number, students have only composed and decomposed numbers 11–19 as ten ones and some more ones throughout this unit, which makes 10 + _____ the most likely way for students to fill in the equations (MP8).
Supports accessibility for: Organization, Conceptual Processing
Required Materials
Materials to Gather
Launch
 Groups of 2
 Give students access to twocolor counters and 10frames.
 “Find the numbers that make each equation true. You can use objects, drawings, or 10frames to help you.”
Activity
 3 minutes: independent work time
 3 minutes: partner work time
Student Facing

\(10 + 5 = \underline{\hspace{1.4 cm}}\)

\(\underline{\hspace{1.4 cm}} + \underline{\hspace{1.4 cm}} = 16\)

\(\underline{\hspace{1.4 cm}} + \underline{\hspace{1.4 cm}} = 19\)

\(\underline{\hspace{1.4 cm}} + \underline{\hspace{1.4 cm}} = 13\)

\(\underline{\hspace{1.4 cm}} + \underline{\hspace{1.4 cm}} = 17\)

\(10 + 1 = \underline{\hspace{1.4 cm}}\)
Student Response
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Activity Synthesis
 Invite a student who represented 17 on a 10frame to share.
 “How do the counters and the 10frame help you fill in the equation?”
 “Where do you see 10 on the 10frame? Where do you see 7 on the 10frame?”
Activity 3: Centers: Choice Time (20 minutes)
Narrative
The purpose of this activity is for students to choose from activities that offer practice with addition and subtraction, writing numbers, and counting objects.
Students choose from any stage of previously introduced centers.
 Make or Break Apart Numbers
 Bingo
 Number Race
 Grab and Count
 Tower Build
Required Materials
Materials to Gather
Required Preparation
 Gather materials from:
 Make or Break Apart Numbers, Stages 1 and 2
 Bingo, Stages 14
 Number Race, Stages 1 and 2
 Grab and Count, Stage 1
 Tower Build, Stages 1 and 2
Launch
 “Today we 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 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.
Bingo
Number Race
Grab and Count
Make or Break Apart Numbers
Tower Build
Activity Synthesis
 “What center do you hope you can keep playing in upcoming lessons? What do you like about that center?”
Lesson Synthesis
Lesson Synthesis
Display \(10 + 9 = 19\).
“Find a way to show that \(10 + 9\) is 19.” (Two students show 19 with 10 fingers and 9 fingers. Students use a full 10frame and 9 counters.)
Cooldown: Unit 6, Section B Checkpoint (0 minutes)
CoolDown
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Student Section Summary
Student Facing
We saw and made numbers 11–19 with fingers and 10frames.
We saw these numbers written as 10 and some more in different ways.
10 and 4 is 14.
\(10 + 4\) is 14.
\(10 + 4 = 14\)