The purpose of this Estimation Exploration is for students to apply their understanding of dividing a whole number by a fraction from previous lessons. The dividend in this expression is much larger than those that students have previously worked with to encourage students to use multiplication to estimate.
Launch
Groups of 2
Display the expression.
“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
98÷51
Record an estimate that is:
too low
about right
too high
Sample Response
Sample responses:
too low: 400 to 450
about right: 470 to 499
too high: 500 or more
Activity Synthesis (Teacher Notes)
“How do you know the value of 98÷51 is less than 500?" (It's less than 100÷51 and that's 500)
Standards
Addressing
5.NF.7.b·Interpret division of a whole number by a unit fraction, and compute such quotients. <em>For example, create a story context for 4 ÷ (1/5), and use a visual fraction model to show the quotient. Use the relationship between multiplication and division to explain that 4 ÷ (1/5) = 20 because 20 × (1/5) = 4.</em>
5.NF.B.7.b·Interpret division of a whole number by a unit fraction, and compute such quotients. <span>For example, create a story context for <span class="math">\(4 \div (1/5)\)</span>, and use a visual fraction model to show the quotient. Use the relationship between multiplication and division to explain that <span class="math">\(4 \div (1/5) = 20~\)</span> because <span class="math">\(20 \times (1/5) = 4\)</span>.</span>
20 min
15 min
Knowledge Components
All skills for this lesson
No KCs tagged for this lesson
Reason about Quotients
10 min
Narrative
The purpose of this Estimation Exploration is for students to apply their understanding of dividing a whole number by a fraction from previous lessons. The dividend in this expression is much larger than those that students have previously worked with to encourage students to use multiplication to estimate.
Launch
Groups of 2
Display the expression.
“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
98÷51
Record an estimate that is:
too low
about right
too high
Sample Response
Sample responses:
too low: 400 to 450
about right: 470 to 499
too high: 500 or more
Activity Synthesis (Teacher Notes)
“How do you know the value of 98÷51 is less than 500?" (It's less than 100÷51 and that's 500)
Standards
Addressing
5.NF.7.b·Interpret division of a whole number by a unit fraction, and compute such quotients. <em>For example, create a story context for 4 ÷ (1/5), and use a visual fraction model to show the quotient. Use the relationship between multiplication and division to explain that 4 ÷ (1/5) = 20 because 20 × (1/5) = 4.</em>
5.NF.B.7.b·Interpret division of a whole number by a unit fraction, and compute such quotients. <span>For example, create a story context for <span class="math">\(4 \div (1/5)\)</span>, and use a visual fraction model to show the quotient. Use the relationship between multiplication and division to explain that <span class="math">\(4 \div (1/5) = 20~\)</span> because <span class="math">\(20 \times (1/5) = 4\)</span>.</span>