Unit 3
What’s the Story?
Lesson 26
Adding and Subtracting Within 20
Expressions and Equations
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Let’s solve story problems.
Unit 3 ● Lesson 26
Learning
Goal
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Subtract 10 or More
Unit 3 ● Lesson 26 ● Warm-up
Find the value of each expression mentally.
Number Talk
Slides are CC BY NC Kendall Hunt Publishing. Curriculum excerpts are CC BY Illustrative Mathematics.
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Solve Related Story Problems
Unit 3 ● Lesson 26 ● Activity 1
She gets some more counters.
Now she has 18 counters.
How many more counters did Elena get?
Show your thinking using drawings, numbers, or words.
Equation: ________________________________
She gets rid of some counters.
Now she has 6 counters.
How many counters did Elena get rid of?
Show your thinking using drawings, numbers, or words.
Equation: ________________________________
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Slides are CC BY NC Kendall Hunt Publishing. Curriculum excerpts are CC BY Illustrative Mathematics.
Solve Related Story Problems
Unit 3 ● Lesson 26 ● Activity 1
Let’s share our equations for each problem.
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Activity Synthesis
Slides are CC BY NC Kendall Hunt Publishing. Curriculum excerpts are CC BY Illustrative Mathematics.
More Story Problems
Unit 3 ● Lesson 26 ● Activity 2
Work with your partner to solve the story problem and create a poster showing how you solved. Be sure to include any equations you used. If you can solve the problem in more than one way, show the different ways and equations.
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Launch
Slides are CC BY NC Kendall Hunt Publishing. Curriculum excerpts are CC BY Illustrative Mathematics.
More Story Problems
Unit 3 ● Lesson 26 ● Activity 2
Story Problem 1 Han has some pencils. He gets 9 pencils from the art store. Now he has 15 pencils. How many pencils did Han have to start? | Story Problem 2 Han has 15 pencils. He gives some pencils to his friends. Now he has 9 pencils. How many pencils did Han give to his friends? |
Story Problem 3 Han has 9 pencils. He gets some more pencils from the art store. Now he has 15 pencils. How many pencils did he get from the art store? | Story Problem 4 Han has 15 pencils. He gives 9 pencils to his friends. How many pencils does Han have now? |
Show your thinking using drawings, words or numbers.
Equation: _________________________________
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Slides are CC BY NC Kendall Hunt Publishing. Curriculum excerpts are CC BY Illustrative Mathematics.
More Story Problems
Unit 3 ● Lesson 26 ● Activity 2
What do you notice about the equations this group used for each problem?
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Activity Synthesis
Slides are CC BY NC Kendall Hunt Publishing. Curriculum excerpts are CC BY Illustrative Mathematics.
What’s the Story?
Unit 3 ● Lesson 26
We have been doing a lot of subtraction using different methods. Tell your partner something new you have learned about subtraction.
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Lesson Synthesis
Slides are CC BY NC Kendall Hunt Publishing. Curriculum excerpts are CC BY Illustrative Mathematics.
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Slides are CC BY NC Kendall Hunt Publishing. Curriculum excerpts are CC BY Illustrative Mathematics.