Multiply Three- and Four-Digit Numbers by One-Digit Numbers
10 min
Narrative
The purpose of an Estimation Exploration is to practice the skill of estimating a reasonable answer based on experience and known information. Listen for the different ways students use their understanding of place value to estimate the area and explain why an estimate is too low or too high.
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 is the area of the rectangle represented by the diagram?
Record an estimate that is:
| too low | about right | too high |
|---|---|---|
Sample Response
- Too low: 1,800–2,000.
- About right: 2,200–2,400
- Too high: 2,500 or higher
Activity Synthesis (Teacher Notes)
- “Is your estimate greater or less than the actual product?” (greater)
- “How could we find the actual product?” (6×400−6×5, or subtract 6×5 from 2,400)
Standards
- 4.NBT.5·Multiply a whole number of up to four digits by a one-digit whole number, and multiply two two-digit numbers, using strategies based on place value and the properties of operations. Illustrate and explain the calculation by using equations, rectangular arrays, and/or area models.
- 4.NBT.B.5·Multiply a whole number of up to four digits by a one-digit whole number, and multiply two two-digit numbers, using strategies based on place value and the properties of operations. Illustrate and explain the calculation by using equations, rectangular arrays, and/or area models.
15 min
20 min
Knowledge Components
All skills for this lesson
No KCs tagged for this lesson
Multiply Three- and Four-Digit Numbers by One-Digit Numbers
10 min
Narrative
The purpose of an Estimation Exploration is to practice the skill of estimating a reasonable answer based on experience and known information. Listen for the different ways students use their understanding of place value to estimate the area and explain why an estimate is too low or too high.
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 is the area of the rectangle represented by the diagram?
Record an estimate that is:
| too low | about right | too high |
|---|---|---|
Sample Response
- Too low: 1,800–2,000.
- About right: 2,200–2,400
- Too high: 2,500 or higher
Activity Synthesis (Teacher Notes)
- “Is your estimate greater or less than the actual product?” (greater)
- “How could we find the actual product?” (6×400−6×5, or subtract 6×5 from 2,400)
Standards
- 4.NBT.5·Multiply a whole number of up to four digits by a one-digit whole number, and multiply two two-digit numbers, using strategies based on place value and the properties of operations. Illustrate and explain the calculation by using equations, rectangular arrays, and/or area models.
- 4.NBT.B.5·Multiply a whole number of up to four digits by a one-digit whole number, and multiply two two-digit numbers, using strategies based on place value and the properties of operations. Illustrate and explain the calculation by using equations, rectangular arrays, and/or area models.