The purpose of this Warm-up is for students to describe the fraction of macaroni and cheese that is left in the pan. While students may notice and wonder many things about this image, the amount of macaroni and cheese in the pan is the important discussion point.
Launch
Groups of 2
Display the image.
“What do you notice? What do you wonder?”
1 minute: quiet think time
Activity
“Discuss your thinking with your partner.”
1 minute: partner discussion
Share and record responses.
What do you notice? What do you wonder?
Student Response
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Advancing Student Thinking
Activity Synthesis
“The picture shows a pan of macaroni and cheese. What other food is baked in pans like this one?” (lasagna, casseroles, cakes)
“About how much macaroni and cheese is left in the pan?” (It’s less than and more than . It looks like it is about .)
Activity 1
Standards Alignment
Building On
Addressing
Building Toward
5.NF.B.4
Apply and extend previous understandings of multiplication to multiply a fraction or whole number by a fraction.
The goal of this activity is for students to draw diagrams that represent a unit fraction multiplied by another unit fraction in context. The macaroni and cheese context was introduced in the Warm-up to motivate students to draw a diagram to represent the pan. The focus in this activity is on the different diagrams students draw and how they represent the same situation (MP2). Some students may identify that Lin ate of the pan. Invite these students to share their observation at the end of the Activity Synthesis when they think about the diagrams in relation to the fraction of the whole pan of macaroni and cheese Lin ate.
Monitor for students who draw different diagrams to show of such as those shown in the Student Responses.
The approaches will later be displayed side by side to help students interpret representations of fractions of fractional quantities and how different diagrams can represent the same situation. Aim to elicit both key mathematical ideas and a variety of student voices, especially students who haven’t shared recently.
MLR2 Collect and Display. Collect the language students use to solve how much of the pan of macaroni Lin ate. Display words and phrases such as: “diagram,” “half,” “fraction,” “divide,” “whole,” “part,” “this much,” “piece.” During the syntheses, invite students to suggest ways to update the display: “What are some other words or phrases we should include?”Invite students to borrow language from the display as needed. Advances: Conversing, Reading
Action and Expression: Develop Expression and Communication. Provide access to a variety of tools: colored pencils, crayons, highlighters that can be used to differentiate between the initial part and the remaining fractional part. Supports accessibility for: Conceptual Processing, Visual-Spatial Processing, Organization
Launch
Groups of 2
“We are going to solve problems about a pan of macaroni and cheese that was served at a big family dinner. Lin is excited that her aunt made her famous baked macaroni and cheese. Tell your partner a story about a dish that you love to eat for dinner.”
1–2 minutes: partner discussion
Activity
3–5 minutes: individual work time
As you monitor for the approaches listed in the activity narrative, consider asking:
“How does your diagram show ?”
“How does your diagram show of ?”
“How did you decide how to partition the rectangle?”
Activity Synthesis
Invite previously selected students to display their work side by side without sharing their thinking.
“Take a minute to look at each of these diagrams.”
Connect students’ approaches to the learning goal by asking:
“How does the diagram represent of of the pan?” (First, the rectangle or pan is divided in half and then a third of one half is shaded.)
“How are the diagrams the same?” (They all show the full pan cut in half. Then they show a half cut into 3 equal pieces and one of those pieces is shaded.)
“How are the diagrams different?” (One diagram cuts the pan in half horizontally and the other two cut it in half vertically. The other cuts into 3 equal pieces are also sometimes horizontal and sometimes vertical.)
“How much of the whole pan did Lin eat?” (Students may say or other fractions.)
Record all responses and revisit this in the Lesson Synthesis.
Activity 2
Standards Alignment
Building On
Addressing
5.NF.B.4.a
Interpret the product as parts of a partition of into equal parts; equivalently, as the result of a sequence of operations . For example, use a visual fraction model to show , and create a story context for this equation. Do the same with . (In general, .)
Continuing the macaroni and cheese context from the previous activity, the purpose of this activity is for students to interpret diagrams showing a fraction of a fraction of the pan. Then students address what fraction of the whole pan the shaded piece of the diagram represents. Because the whole pan is not subdivided, students may need to add the extra divisions or think carefully to identify the fraction of the whole pan represented by the diagrams. To identify that the shaded pieces in the two diagrams have equal area students may:
Cut out and compare the shaded pieces explicitly.
Reason that they are each or of the same amount.
Reason that they are each of the whole.
Launch
Groups of 2
Activity
1–2 minutes: quiet think time
5–8 minutes: partner discussion
Monitor for students who:
Extend the dashed lines in Diagram A to determine that of the whole square is darkly shaded.
Partition the rest of the square in Diagram B to determine that of the whole square is darkly shaded.
Activity Synthesis
Ask previously selected students to share in the given order.
“How does each diagram represent of ?” (They each show shaded in the lighter blue and then of that half is shaded darker.)
“How do we know the darkly shaded pieces are the same size?” (I cut them out to check. They are both of . They both represent of the whole pan.)
If not already mentioned by students, ask: “How can we figure out how much of the whole pan of macaroni cheese the dark shaded piece represents?” (We can extend the lines in Diagram A and we can partition the rest of the square in Diagram B.)
“ of is equal to how much of the whole pan of macaroni and cheese?” ( of the whole pan.)
Lesson Synthesis
“Today we drew diagrams to represent fractions of fractions. What did you learn about fractions of fractions?” (They are pieces of pieces.)
Consider asking students to respond in their journals.
Refer to the diagrams students drew to show of of a pan of macaroni and cheese.
“How much of the whole pan of macaroni and cheese did Lin eat? How do you know?” (. I would need to divide the whole rectangle, not just the one half that was left. Then there would be 6 equal parts and Lin ate one of them.)
Standards Alignment
Building On
Addressing
Building Toward
5.NF.B.4.a
Interpret the product as parts of a partition of into equal parts; equivalently, as the result of a sequence of operations . For example, use a visual fraction model to show , and create a story context for this equation. Do the same with . (In general, .)