This Warm-up prompts students to carefully analyze and compare equations. In making comparisons, students have a reason to use language precisely (MP6). The activity also enables the teacher to hear the terminologies students know and how they talk about characteristics of addition and subtraction equations as well as equations with an unknown number.
Launch
Groups of 2
Display the equations.
“Pick 3 that go together. Be ready to share why they go together.”
1 minute: quiet think time
Activity
“Discuss your thinking with your partner.”
2–3 minutes: partner discussion
Share and record responses.
Which 3 go together?
Student Response
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Advancing Student Thinking
Activity Synthesis
Display Equation D.
“Think of a story problem that could match this equation.”
“In this lesson, we will match more equations to story problems.”
Activity 1
Standards Alignment
Building On
Addressing
1.OA.A.1
Use addition and subtraction within 20 to solve word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using objects, drawings, and equations with a symbol for the unknown number to represent the problem.See Glossary, Table 1.
The purpose of this activity is to sort story problems with unknowns in all positions. Students sort the story problems by whether they are addition or subtraction problems. This sorting task gives students opportunities to analyze story problems closely and make connections (MP2, MP7). Some stories include actions that would be represented by one operation, but may be solved using the opposite operation. Students may sort these problems into either category as long as they can explain how they sort.
For example, consider this Take From, Start Unknown story problem:
Clare has some stickers.
She gives 9 of them to her friends.
She has 5 stickers left.
How many stickers did Clare have to start with?
In the last lesson, students related this type of problem to a subtraction equation (). This equation represents the action in the story. However, students may also think of an equation that shows how they would solve the problem (). This concept is discussed in the Activity Synthesis to prepare students to identify more than one equation to match these story problems in the next activity.
Engagement: Develop Effort and Persistence. Chunk this task into more manageable parts. Give students a subset of the cards to start with and introduce the remaining cards once students have sorted the initial set of cards. Supports accessibility for: Organization, Attention
Launch
Groups of 2
Give each group a set of cards and access to connecting cubes in towers of 10 and singles.
“We have been solving stories about people doing different arts and crafts. Making collages is another popular craft.”
Display the word “collage” for all to see and invite students to share what they know about making a collage.
If needed ask, “What materials can you use to make a collage?” (stickers, pictures, stamps, markers, glitter, glue)
Activity
“This set of cards includes stories about students who made collages. Sort the cards by whether they have an addition story problem or a subtraction story problem. Work with your partner to explain why the cards go together.”
10 minutes: partner work time
Monitor for groups who put the same story problem in different categories.
None
Student Response
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Activity Synthesis
Display the problems that students sorted into different groups, such as Cards A, D or F.
“How is this an addition story problem? How is this a subtraction story problem?” (To solve Card A’s problem, I can think about how many pictures to add to 8 to get to 11, or I can think 11−8 to find how many animal pictures Jada uses.)
Repeat with other problems, as time permits.
Activity 2
Standards Alignment
Building On
Addressing
1.OA.A.1
Use addition and subtraction within 20 to solve word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using objects, drawings, and equations with a symbol for the unknown number to represent the problem.See Glossary, Table 1.
The purpose of this activity is to match equations to the story problems from the previous activity. Each story has several equations listed, two of which match the story. Students are encouraged to find both equations. However, it is more important that students can explain how an equation represents what is happening in the story or how it is used to solve the story. In the launch, students make sense of a familiar diagram to encourage them to use objects or drawings to represent the story if it will help them find the matching equations.
In order to match stories with equations, students reason abstractly and quantitatively (MP2) as they interpret both the numbers and the operations in the equations in terms of a context.
MLR8 Discussion Supports Display the following sentence frames to support partner discussion: “I think the equations _____ and _____ match the story problem because…,” “I agree because…,” and “I disagree because…” Advances: Speaking, Conversing
Launch
Groups of 2
Give students access to connecting cubes in towers of 10 and singles.
Display the diagram and read the first story problem. Do not display the equations.
“How does the diagram represent the story problem?” (The 8 white cubes show the pictures of people. The 3 blue cubes were added to get to a total of 11 pictures. So the 3 blue cubes show the pictures of animals.)
1 minute: quiet think time
1 minute: partner discussion
“Which equations match the story?”
Display the equations.
30 seconds: quiet think time
1 minute: partner discussion
Monitor for students who chose the second and third equations.
Invite students to share.
If needed: “How does the diagram match the equation?”
If needed: “There is an addition and subtraction equation that can match this problem.”
Activity
Read the Task Statement.
Tell students they can use drawings to represent the problem, if it helps.
10 minutes: partner work time.
Circle the 2 equations that match each story.
Jada uses 8 pictures of people.
She also uses some pictures of animals.
Altogether she uses 11 pictures.
How many pictures of animals does she use?
Kiran has 19 pictures.
He gives some to his sister.
Now, he has 11 pictures left.
How many pictures did Kiran give to his sister?
Han’s collage has 16 stamps.
Lin’s collage has 10 fewer stamps.
How many stamps does Lin’s collage have?
Elena uses 9 more stickers than Andre.
Andre uses 5 stickers.
How many stickers does Elena use?
Noah has 6 stamps.
Tyler has 16 stamps.
How many fewer stamps does Noah have than Tyler?
Clare has some stickers.
She gives 9 of them to her friends.
She has 5 stickers left.
How many stickers did Clare have to start?
If you have time: Choose a story problem to solve.
Show your thinking using drawings, numbers, or words.
Student Response
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Advancing Student Thinking
Activity Synthesis
Display the problem about Noah and Tyler and a tower of 6 cubes and a tower of 16 cubes.
“Use the cubes to explain how we can use addition to solve this problem.”
Repeat for subtraction.
Lesson Synthesis
Display this problem from the lesson:
Kiran has 19 pictures.
He gives some to his sister.
Now he has 11 pictures left.
How many pictures did Kiran give to his sister?
Display:
“Which equation best matches the actions in this story? Why?” ( because in the story Kiran starts with 19 pictures, he gives some away, and the story tells us he has 11 left.)
“Which equation matches how you would solve this problem? Why?” (I would use because I if I take away the pictures he has left, I will know how many he gave to his sister. I would use because I would rather add than subtract. I can add to the 11 pictures he had left until I get to 19 and that will tell me how many he gave to his sister.)
Complete Cool-Down
Standards Alignment
Building On
Addressing
1.OA.C.6
Add and subtract within 20, demonstrating fluency for addition and subtraction within 10. Use strategies such as counting on; making ten (e.g., ); decomposing a number leading to a ten (e.g., ); using the relationship between addition and subtraction (e.g., knowing that , one knows ); and creating equivalent but easier or known sums (e.g., adding by creating the known equivalent ).
Add and subtract within 20, demonstrating fluency for addition and subtraction within 10. Use strategies such as counting on; making ten (e.g., ); decomposing a number leading to a ten (e.g., ); using the relationship between addition and subtraction (e.g., knowing that , one knows ); and creating equivalent but easier or known sums (e.g., adding by creating the known equivalent ).
Add and subtract within 20, demonstrating fluency for addition and subtraction within 10. Use strategies such as counting on; making ten (e.g., ); decomposing a number leading to a ten (e.g., ); using the relationship between addition and subtraction (e.g., knowing that , one knows ); and creating equivalent but easier or known sums (e.g., adding by creating the known equivalent ).
