Points on the Number Line
5 min
Teacher Prep
Setup
Narrative
The purpose of this activity is to prime students to locate negative fractions on a number line by analyzing a number’s position relative to landmarks on the number line. In later activities, students will use the same process of discerning which two numbers a value is between to describe negative rational numbers.
Launch
Arrange students in groups of 2. Give students 2 minutes of quiet think time, and follow with a whole-class discussion.
Student Task
Which of the following numbers could be represented by point B?
2.45
52
25
1035
2.11
-2.5
Sample Response
2.45 and 25. Sample reasoning: Both values are halfway or about halfway between 2 and 3. The fraction 52 is less than 1 and is too small to be point B. The fraction 1035 is equivalent to 3.5, which would be between 3 and 4. The number 2.11 is also located between 2 and 3 on the number line, but it would be closer to 2.
Activity Synthesis (Teacher Notes)
The goal of this discussion is for students to understand how they can use landmarks on the number line (in this case, 2 and 3) and their knowledge of fractions to correctly place a number on a number line. Ask students:
- “Were there any responses you could tell right away were not point B? How?” (52 is less than 1, but B is between 2 and 3.)
- “Were there any responses you had to think harder about?" (2.11 is also between 2 and 3.)
- “What part of the number line was useful when trying to decide which numbers could be point B?” (The numbers 2 and 3 on the number line told me that the number had to have a value somewhere between 2 and 3.)
Standards
- 3.NF.A·Develop understanding of fractions as numbers.
- 3.NF.A·Develop understanding of fractions as numbers.
- 4.NF.C·Understand decimal notation for fractions, and compare decimal fractions.
- 4.NF.C·Understand decimal notation for fractions, and compare decimal fractions.
10 min
20 min
Knowledge Components
All skills for this lesson
No KCs tagged for this lesson
Points on the Number Line
5 min
Teacher Prep
Setup
Narrative
The purpose of this activity is to prime students to locate negative fractions on a number line by analyzing a number’s position relative to landmarks on the number line. In later activities, students will use the same process of discerning which two numbers a value is between to describe negative rational numbers.
Launch
Arrange students in groups of 2. Give students 2 minutes of quiet think time, and follow with a whole-class discussion.
Student Task
Which of the following numbers could be represented by point B?
2.45
52
25
1035
2.11
-2.5
Sample Response
2.45 and 25. Sample reasoning: Both values are halfway or about halfway between 2 and 3. The fraction 52 is less than 1 and is too small to be point B. The fraction 1035 is equivalent to 3.5, which would be between 3 and 4. The number 2.11 is also located between 2 and 3 on the number line, but it would be closer to 2.
Activity Synthesis (Teacher Notes)
The goal of this discussion is for students to understand how they can use landmarks on the number line (in this case, 2 and 3) and their knowledge of fractions to correctly place a number on a number line. Ask students:
- “Were there any responses you could tell right away were not point B? How?” (52 is less than 1, but B is between 2 and 3.)
- “Were there any responses you had to think harder about?" (2.11 is also between 2 and 3.)
- “What part of the number line was useful when trying to decide which numbers could be point B?” (The numbers 2 and 3 on the number line told me that the number had to have a value somewhere between 2 and 3.)
Standards
- 3.NF.A·Develop understanding of fractions as numbers.
- 3.NF.A·Develop understanding of fractions as numbers.
- 4.NF.C·Understand decimal notation for fractions, and compare decimal fractions.
- 4.NF.C·Understand decimal notation for fractions, and compare decimal fractions.