Curriculum  /  Math  /  2nd Grade  /  Unit 2: Adding and Subtracting Within 100  /  Lesson 10

Adding and Subtracting Within 100

Lesson 10

Math

Unit 2

2nd Grade

Lesson 10 of 21

Objective

Relate addition and subtraction to subtract within 100.

Student-Facing

I can use addition thinking to subtract. 

Common Core Standards

Core Standards

  • 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

  • 1.NBT.C.4
  • 1.NBT.C.5
  • 1.NBT.C.6

Criteria for Success

  1. Recognize the relationship between subtraction and addition equations in subtraction or missing addend situation types.
  2. Solve subtraction equations using the relationship between addition equations by adding up to the whole or using counting on strategies.

Tips for Teachers

In this lesson students will see a mix of subtraction and missing addend situations that call for subtraction. Relate back to their work in Unit 1, Lesson 7 if students need additional support. 

Warm Up

5-10 minutes

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Anchor Tasks

15-25 minutes

Problem 1

Alicia solved 36 - 23 = ? by doing the following. 

23 +  10   = 33

33 +  3  = 36

10 + 3 = 13

Use Alicia’s strategy to solve 43 - 32 = _____.

Purpose

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Problem 2

Find the missing number that makes each equation true. Show your thinking with pictures or numbers.

a.   19 + _____ = 30

b.   25 + _____ = 53

c.   59 + _____ = 71

d.   77 + _____ = 100

Purpose

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Problem 3

Find the missing number that makes each statement true. Use addition thinking to help you solve.

a.   83 - 51 =  _____

b.   79 - 29 = _____

c.   68 - _____ = 46

Purpose

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Problem Set

15-20 minutes

Target Task

5-10 minutes

Solve. Show your thinking with pictures or numbers. 

a.   55 - 25 = _____

b.   32 + _____ = 64

c.   87 - 50 = _____

d.   51 + _____ = 92

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.

Word Problems and Fluency Activities

Next

Use place value knowledge to subtract with one decomposition.

Lesson 11
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Lesson Map

A7CB09C2-D12F-4F55-80DB-37298FF0A765

Topic A: Adding & Subtracting with Multiples of Ten

Topic B: Strategies for Adding within 100

Topic C: Strategies for Subtracting within 100

Topic D: Working within 100 and Categorical Data

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