Lesson 6 | Adding and Subtracting Within 100 | 2nd Grade Mathematics

Objective

Use place value knowledge to add within 100.

Student-Facing

I can use place value knowledge to add.

Common Core Standards

Core Standards

The core standards covered in this lesson

2.NBT.B.5 — Fluently add and subtract within 100 using strategies based on place value, properties of operations, and/or the relationship between addition and subtraction.

Number and Operations in Base Ten

2.NBT.B.5 — Fluently add and subtract within 100 using strategies based on place value, properties of operations, and/or the relationship between addition and subtraction.

Foundational Standards

The foundational standards covered in this lesson

1.NBT.C.4

Number and Operations in Base Ten

1.NBT.C.4 — Add within 100, including adding a two-digit number and a one-digit number, and adding a two-digit number and a multiple of 10, 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 and explain the reasoning used. Understand that in adding two-digit numbers, one adds tens and tens, ones and ones; and sometimes it is necessary to compose a ten.
1.NBT.C.5

Number and Operations in Base Ten

1.NBT.C.5 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
1.NBT.C.6

Number and Operations in Base Ten

1.NBT.C.6 — Subtract multiples of 10 in the range 10-90 from multiples of 10 in the range 10-90 (positive or zero differences), 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 and explain the reasoning used.

Criteria for Success

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

Understand that two-digit numbers can be added by combining like units. For example adding the tens of both addends and the ones of both addends.
Combine the total tens and ones to find the sum of both combined addends.

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 the following problems in two ways.

a. 18 + 31 =

b. 16 + 47 =

Purpose

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Problem 2

Use your knowledge of tens and ones to solve. Show your thinking.

a. 15 + 80 =

b. 65 + 33 =

c. 59 + 22 =

d. 73 + 21 =

Purpose

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Problem 3

a. Pat spilled water on their worksheet. Fill in the missing numbers they used to solve.

56 + 33

+ 30 =

6 + 3 =

80 + =

b. Explain Pat’s strategy.

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. Xavier started to solve the following problem. Finish his work.

48 + 21 =

40 + = 60

8 + 1 =

60 + =

b. Solve the following using Xavier’s strategy.

63 + 35 = _____

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 100

Objective

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Student-Facing

Common Core Standards

Core Standards

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

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Warm Up

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Anchor Tasks

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Problem 1

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Purpose

Problem 2

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Purpose

Problem 3

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Purpose

Problem Set

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Target Task

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Student Response

Additional Practice

Word Problems and Fluency Activities

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