Nearest Multiples of 10 and of 100
10 min
Narrative
The purpose of this Estimation Exploration is for students to think about what value a point on the number line could represent. The only labeled tick marks are hundreds, so students need to reason about what numbers are in between and how far the point is from the labeled numbers.
Launch
- Groups of 2
- Display the image.
- “What is an estimate that’s too high? Too low? About right?”
- 1 minute: quiet think time
Teacher Instructions
- “Discuss your thinking with your partner.”
- 1 minute: partner discussion
- Record responses.
Student Task
What number could the point on the number line represent?
Record an estimate that is:
| too low | about right | too high |
|---|---|---|
Solution Steps (5)
- 1View number line from 0 to 200→Point is between 100 and 200, closer to 100
- 2Estimate distance from 100→Point is about 30-40 units from 100
- 3Provide too low estimate→Less than 130
- 4Provide about right estimate→130-140
- 5Provide too high estimate→Greater than 140
Sample Response
Sample responses:
- Too low: less than 130
- About right: 130–140
- Too high: greater than 140
Activity Synthesis (Teacher Notes)
- Consider asking:
- “Is anyone’s estimate less than _____? Is anyone’s estimate greater than _____?”
- “Based on this discussion, does anyone want to revise their estimate?”
- “What would help us be more sure of our estimate?” (More tick marks that are equally spaced. Marks of multiples of 10.)
Standards
Building On
- 2.MD.6·Represent whole numbers as lengths from 0 on a number line diagram with equally spaced points corresponding to the numbers 0, 1, 2, …, and represent whole-number sums and differences within 100 on a number line diagram.
- 2.MD.B.6·Represent whole numbers as lengths from 0 on a number line diagram with equally spaced points corresponding to the numbers 0, 1, 2, …, and represent whole-number sums and differences within 100 on a number line diagram.
Building Toward
- 3.NBT.1·Use place value understanding to round whole numbers to the nearest 10 or 100.
- 3.NBT.A.1·Use place value understanding to round whole numbers to the nearest 10 or 100.
20 min
15 min
Knowledge Components
All skills for this lesson
Role Legend
Target
Essential
Supporting
Foundational
All lesson KCs
1 skills
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Nearest Multiples of 10 and of 100
10 min
Narrative
The purpose of this Estimation Exploration is for students to think about what value a point on the number line could represent. The only labeled tick marks are hundreds, so students need to reason about what numbers are in between and how far the point is from the labeled numbers.
Launch
- Groups of 2
- Display the image.
- “What is an estimate that’s too high? Too low? About right?”
- 1 minute: quiet think time
Teacher Instructions
- “Discuss your thinking with your partner.”
- 1 minute: partner discussion
- Record responses.
Student Task
What number could the point on the number line represent?
Record an estimate that is:
| too low | about right | too high |
|---|---|---|
Solution Steps (5)
- 1View number line from 0 to 200→Point is between 100 and 200, closer to 100
- 2Estimate distance from 100→Point is about 30-40 units from 100
- 3Provide too low estimate→Less than 130
- 4Provide about right estimate→130-140
- 5Provide too high estimate→Greater than 140
Sample Response
Sample responses:
- Too low: less than 130
- About right: 130–140
- Too high: greater than 140
Activity Synthesis (Teacher Notes)
- Consider asking:
- “Is anyone’s estimate less than _____? Is anyone’s estimate greater than _____?”
- “Based on this discussion, does anyone want to revise their estimate?”
- “What would help us be more sure of our estimate?” (More tick marks that are equally spaced. Marks of multiples of 10.)
Standards
Building On
- 2.MD.6·Represent whole numbers as lengths from 0 on a number line diagram with equally spaced points corresponding to the numbers 0, 1, 2, …, and represent whole-number sums and differences within 100 on a number line diagram.
- 2.MD.B.6·Represent whole numbers as lengths from 0 on a number line diagram with equally spaced points corresponding to the numbers 0, 1, 2, …, and represent whole-number sums and differences within 100 on a number line diagram.
Building Toward
- 3.NBT.1·Use place value understanding to round whole numbers to the nearest 10 or 100.
- 3.NBT.A.1·Use place value understanding to round whole numbers to the nearest 10 or 100.