To the Number Line
10 min
Narrative
The purpose of this Warm-up is to elicit the idea that number lines can be partitioned into intervals smaller than 1, which will be useful when students see number lines partitioned into fractions in a later activity. While students may notice and wonder about many things, the idea that fractions can be represented on the number line is the important discussion point. Students do not need to identify in the Warm-up that the tick mark on one number line shows 21, as it will be the focus later in the lesson.
This prompt gives students opportunities to look for and make use of structure (MP7). The specific structure they might notice is that each number line is partitioned in half.
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?
Solution Steps (3)
- 1Observe number line from 0 to 10→Middle tick mark is at 5 (halfway between 0 and 10)
- 2Observe number line from 0 to 1→Middle tick mark is halfway between 0 and 1
- 3Connect to fraction understanding→Halfway point on 0-1 line represents 1/2
Sample Response
- There’s a number line that goes from 0 to 10 and a number line that goes from 0 to 1.
- Both have a tick mark in the middle.
- Only 0 and 10 and 0 and 1 are labeled.
- What numbers are at the tick marks?
- Why are the number lines split in half?
- Could we put more numbers on the number lines?
Activity Synthesis (Teacher Notes)
- “What do you know about the number each tick mark represents?” (On the first number line, it is 5 because it is halfway between 0 and 10. On the second number line, I think it is 21 because it is halfway between 0 and 1.)
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.
10 min
25 min
Knowledge Components
All skills for this lesson
To the Number Line
10 min
Narrative
The purpose of this Warm-up is to elicit the idea that number lines can be partitioned into intervals smaller than 1, which will be useful when students see number lines partitioned into fractions in a later activity. While students may notice and wonder about many things, the idea that fractions can be represented on the number line is the important discussion point. Students do not need to identify in the Warm-up that the tick mark on one number line shows 21, as it will be the focus later in the lesson.
This prompt gives students opportunities to look for and make use of structure (MP7). The specific structure they might notice is that each number line is partitioned in half.
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?
Solution Steps (3)
- 1Observe number line from 0 to 10→Middle tick mark is at 5 (halfway between 0 and 10)
- 2Observe number line from 0 to 1→Middle tick mark is halfway between 0 and 1
- 3Connect to fraction understanding→Halfway point on 0-1 line represents 1/2
Sample Response
- There’s a number line that goes from 0 to 10 and a number line that goes from 0 to 1.
- Both have a tick mark in the middle.
- Only 0 and 10 and 0 and 1 are labeled.
- What numbers are at the tick marks?
- Why are the number lines split in half?
- Could we put more numbers on the number lines?
Activity Synthesis (Teacher Notes)
- “What do you know about the number each tick mark represents?” (On the first number line, it is 5 because it is halfway between 0 and 10. On the second number line, I think it is 21 because it is halfway between 0 and 1.)
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.