Extending the Number Line: Lesson 2

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Introduction

Read the Headline Story to the students. Encourage them to use logical reasoning to draw conclusions about the coins.

Headline Story

Kyra, Martin, and Joel each have some coins. Kyra’s coins have a value that is a multiple of 9¢. Martin has a multiple of 8¢. Together, the three children have 35¢. How much might they each have?

Possible student responses

All of the children have at least 1 coin.
Kyra might have 9¢, 18¢, or 27¢; Martin might have 8¢, 16¢, 24¢, or 32¢.
If Kyra has 27¢, then Martin could have 8¢ and Joel would have no coins, so Kyra must not have 27¢.
We could make a table showing what Joel might have:

	What Martin has
What Kyra has		9¢	18¢	27¢
	8¢	18¢	9¢	**
	16¢	10¢	1¢	**
	24¢	2¢	**	**
	32¢	**	**	**

Joel must have at least 1¢ and no more than 18¢.

Headline Story

Extending the Number Line, #2

Introduction

Headline Story

Possible student responses