# The Craft of Word Problems

## CONTENTS OF CURRICULUM UNIT 04.05.01

- Narrative
- Place Value
- Addition and Subtraction (within 10)
- Fact Families
- Addition and Subtraction (within 20)
- Addition and Subtraction with and without regrouping
- Strategies for solving problems
- Lesson 1
- Lesson 2
- Lesson 3
- Lesson 4
- Lesson 5
- Lesson 6
- In the Future
- Mathematics Standards
- Bibliography for Teachers and Students

### Unit Guide

## The Relationship between Addition and Subtraction in Problem Solving

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## Lesson 3

Focus on four basic problems that relate. Discuss the problems. Students may use manipulatives to solve the problems. Discuss how these problems are the same and how they are different.

Objectives

To have students use the four basic strategies to solve a set of word problems.

To have students understand and discuss the relationship between this set of problems.

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Problem 1
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Dave ate 4 cherries. Sal ate 2 cherries. How many cherries did they eat altogether?

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Problem 2
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If Dave ate 4 cherries and Sal ate 2 cherries, how many more did Dave eat?

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Problem 3
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Dave and Sal together ate 6 cherries. If Sal ate 2 cherries, how many did Dave eat?

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Problem 4

Two boys ate a total of 6 cherries. If Dave ate 4, how many did Sal eat?

In this set of problems, I threw them a “curve ball.” I wanted to give my students a problem that doesn’t belong to the fact family. This will help me understand how well they know what a fact family is. Problem 2 is different from the problems given in the two previous lessons. I would begin by asking the students the following questions:

Which problem does not belong? Why?

How is this problem different?

Why is this problem different from the other three problems? Why doesn’t it “fit in?”

Have you ever seen a problem like this before?

This problem is not from the same fact family. It is not a difficult problem but it is different. I would ask students how they would solve this problem and have students share this with one another. Then I would ask students how we could change this word problem or write a new word problem to fit in with the existing fact family. Students may wish to discuss this with a partner and present their ideas to class. Teachers may find it interesting to see how difficult or easy this task may be.