Lesson 25 | Adding and Subtracting Within 1,000 | 2nd Grade Mathematics

Objective

Solve and explain strategies when adding and subtracting within 1,000.

Student-Facing

I can solve addition and subtraction problems within 1,000 and explain my thinking.

Common Core Standards

Core Standards

The core standards covered in this lesson

2.NBT.B.7 — Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.

Number and Operations in Base Ten

2.NBT.B.7 — Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.
2.NBT.B.9 — Explain why addition and subtraction strategies work, using place value and the properties of operations. Explanations may be supported by drawings or objects.

Number and Operations in Base Ten

2.NBT.B.9 — Explain why addition and subtraction strategies work, using place value and the properties of operations. Explanations may be supported by drawings or objects.

Foundational Standards

The foundational standards covered in this lesson

1.NBT.B.2

Number and Operations in Base Ten

1.NBT.B.2 — Understand that the two digits of a two-digit number represent amounts of tens and ones. Understand the following as special cases:
2.NBT.A.1

Number and Operations in Base Ten

2.NBT.A.1 — Understand that the three digits of a three-digit number represent amounts of hundreds, tens, and ones; e.g., 706 equals 7 hundreds, 0 tens, and 6 ones. Understand the following as special cases:
2.NBT.A.2

Number and Operations in Base Ten

2.NBT.A.2 — Count within 1000; skip-count by 5s, 10s, and 100s.

Criteria for Success

The essential concepts students need to demonstrate or understand to achieve the lesson objective

Solve addition computations within 1,000 and explain strategies used to solve.
Solve subtraction computations within 1,000 and explain strategies used to solve.
Use relationship between addition and subtraction to check solutions within 1,000.

Tips for Teachers

Suggestions for teachers to help them teach this lesson

Use the co-created checklist from Lesson 24 to support student explanations during today's lesson.

Lesson Materials

Dice (1 per student)

Warm Up

5-10 minutes

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Anchor Tasks

Tasks designed to teach criteria for success of the lesson, and guidance to help draw out student understanding

15-25 minutes

Problem 1

Solve each of the following in two ways. Explain one of your ways.

a. 740 - 298 =

b. 359 + 473 =

Purpose

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Problem 2

a. Subtract to find the difference.

478 - 290 =

Explain your strategy and why it works.

b. Show how you could use addition to check your solution. Explain your strategy and why it works.

Purpose

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Problem Set

15-20 minutes

Target Task

A task that represents the peak thinking of the lesson - mastery will indicate whether or not objective was achieved

5-10 minutes

a. Solve to find the difference. Show your thinking.

735 - 345 = _____

b. Explain the strategy you used to add and why it works.

c. Show how you could use addition to check your solution.

Student Response

Additional Practice

Daily Word Problems, Warm Ups, and Center Activities are aligned to the content of the unit but not necessarily to the lesson objective, therefore feel free to use them anytime during your school day.

Adding and Subtracting Within 1,000

Objective

Add a note

Are You Sure?

Student-Facing

Common Core Standards

Core Standards

Number and Operations in Base Ten

Number and Operations in Base Ten

Foundational Standards

Number and Operations in Base Ten

Number and Operations in Base Ten

Number and Operations in Base Ten

Criteria for Success

Add a note

Are You Sure?

Tips for Teachers

Add a note

Are You Sure?

Lesson Materials

Warm Up

Add a note

Are You Sure?

Anchor Tasks

Add a note

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Problem 1

Add a note

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Purpose

Problem 2

Add a note

Are You Sure?

Purpose

Problem Set

Add a note

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Target Task

Add a note

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Student Response

Additional Practice

Word Problems and Fluency Activities

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