Unit 3, Lesson 8

Subtraction Algorithms (Part 1)

Grade 3

Warm-up

Number Talk: Subtraction Strategies

Standards Alignment

Building On

Addressing

Building Toward

Find the value of each expression mentally.

Are You Ready for More?

Activity 1

From Drawings to an Algorithm

Standards Alignment

Building On

Addressing

Building Toward

Jada and Kiran each found the value of . Their work is shown.

Jada’s drawing

Student representation of a base ten diagram with 3 hundreds, 2 crossed out, 9 tens with 2 crossed out with arrow pointing to 1 ten with 4 crossed out and a one, crossed out.

Kiran’s algorithm

<p>Subtraction. Three-hundred plus ninety plus one, minus two-hundred plus ten plus five.</p>

Explain how Kiran’s algorithm starts.
Explain how Kiran recorded decomposing 1 ten into more ones.
Finish Kiran’s work.

Are You Ready for More?

Activity 2

Card Sort: Diagrams and Algorithms

Standards Alignment

Building On

Addressing

Building Toward

Your teacher will give you a set of cards. Match each diagram to an algorithm. Be ready to explain your reasoning.

Are You Ready for More?

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Unit 3, Lesson 8

Subtraction Algorithms (Part 1)

Grade 3

Warm-up

Number Talk: Subtraction Strategies

Standards Alignment

Building On

Addressing

Building Toward

Find the value of each expression mentally.

Are You Ready for More?

Activity 1

From Drawings to an Algorithm

Standards Alignment

Building On

Addressing

Building Toward

Jada and Kiran each found the value of . Their work is shown.

Jada’s drawing

Kiran’s algorithm

Explain how Kiran’s algorithm starts.
Explain how Kiran recorded decomposing 1 ten into more ones.
Finish Kiran’s work.

Are You Ready for More?

Activity 2

Card Sort: Diagrams and Algorithms

Standards Alignment

Building On

Addressing

Building Toward

Your teacher will give you a set of cards. Match each diagram to an algorithm. Be ready to explain your reasoning.

Are You Ready for More?

Have feedback on the curriculum?

Help us improve by sharing suggestions or reporting issues.

Submit Feedback

Lesson 8

Subtraction Algorithms (Part 1)

Warm-up

Number Talk: Subtraction Strategies

Standards Alignment

3.NBT.2

Are You Ready for More?

Activity 1

From Drawings to an Algorithm

Standards Alignment

3.NBT.2

Are You Ready for More?

Activity 2

Card Sort: Diagrams and Algorithms

Standards Alignment

3.NBT.2

Are You Ready for More?

Have feedback on the curriculum?

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Lesson 8

Subtraction Algorithms (Part 1)

Warm-up

Number Talk: Subtraction Strategies

Standards Alignment

3.NBT.2

Are You Ready for More?

Activity 1

From Drawings to an Algorithm

Standards Alignment

3.NBT.2

Are You Ready for More?

Activity 2

Card Sort: Diagrams and Algorithms

Standards Alignment

3.NBT.2

Are You Ready for More?

Have feedback on the curriculum?