Relate Fractions to Benchmarks
10 min
Narrative
The purpose of this Warm-up is for students to recognize that two values of reference are needed to determine the number that a point on the number line represents. The numbers 0 and 1 are commonly used when the numbers of interest are small. With only one number shown (for example, only a 0 or a 1), we can’t tell what number a point represents, though we can tell if the number is greater or less than the given number. These understandings will be helpful later in the lesson, as students determine the size of fractions relative to 21 and 1.
Launch
- Groups of 2
- Display the image.
- “What do you notice? What do you wonder?”
- 1 minute: quiet think time
Teacher Instructions
- “Discuss your thinking with your partner.”
- 1 minute: partner discussion
- Share and record responses.
Student Task
What do you notice? What do you wonder?
Sample Response
Students may notice:
- A number line has a point on it.
- The point is on the 6th tick mark from 0.
- There are no other numbers on the line other than 0.
- There are 10 tick marks on the line.
- The point shows a number greater than 0.
Students may wonder:
- Why isn’t there a label for 1?
- Is it possible to tell what number the point represents if there are no other labels?
- Can we assume that the last tick mark represents 1?
Activity Synthesis (Teacher Notes)
- “How would we know what number the point represents? What’s missing and needs to be there?” (A label for one of the tick marks so that we’d know what each space between tick marks represents.)
Standards
- 3.NF.2·Understand a fraction as a number on the number line; represent fractions on a number line diagram.
- 3.NF.A.2·Understand a fraction as a number on the number line; represent fractions on a number line diagram.
20 min
15 min
Knowledge Components
All skills for this lesson
No KCs tagged for this lesson
Relate Fractions to Benchmarks
10 min
Narrative
The purpose of this Warm-up is for students to recognize that two values of reference are needed to determine the number that a point on the number line represents. The numbers 0 and 1 are commonly used when the numbers of interest are small. With only one number shown (for example, only a 0 or a 1), we can’t tell what number a point represents, though we can tell if the number is greater or less than the given number. These understandings will be helpful later in the lesson, as students determine the size of fractions relative to 21 and 1.
Launch
- Groups of 2
- Display the image.
- “What do you notice? What do you wonder?”
- 1 minute: quiet think time
Teacher Instructions
- “Discuss your thinking with your partner.”
- 1 minute: partner discussion
- Share and record responses.
Student Task
What do you notice? What do you wonder?
Sample Response
Students may notice:
- A number line has a point on it.
- The point is on the 6th tick mark from 0.
- There are no other numbers on the line other than 0.
- There are 10 tick marks on the line.
- The point shows a number greater than 0.
Students may wonder:
- Why isn’t there a label for 1?
- Is it possible to tell what number the point represents if there are no other labels?
- Can we assume that the last tick mark represents 1?
Activity Synthesis (Teacher Notes)
- “How would we know what number the point represents? What’s missing and needs to be there?” (A label for one of the tick marks so that we’d know what each space between tick marks represents.)
Standards
- 3.NF.2·Understand a fraction as a number on the number line; represent fractions on a number line diagram.
- 3.NF.A.2·Understand a fraction as a number on the number line; represent fractions on a number line diagram.