To emphasize the concept that the size of the fraction depends on the size of the unit whole, display the Pizza Delivery Master.
Ask students to discuss the following displayed question with a partner.
- Joe Smart ordered a pizza from Red Hot Pizza and Moe Smart ordered a pizza from Rick's Pizzaria. Joe ate half his pizza and Moe ate three-fourths of his. Who ate more? Be ready to explain your answer.
Students should be able to explain that it is impossible to tell who ate more without knowing how large each whole pizza was. The size of a fractional part depends on the size of the whole.
Read the vignette in the What Is 1? section as a class. Assign Check-In: Questions 16–20 in the Student Guide to develop the corresponding idea that size of the whole can be determined if we know the size of a given fraction.
Before students begin to work on Question 20 direct them to the Math Practices page in the Reference Section of the Student Guide. Ask students to read Math Practice Expectations 2 and 5 carefully and to think about how these math practices can help them think about the work they are going to do.
- Once you know what the question is asking what tools and strategies can you use to answer this question? (Since the question is about fractions you can use fraction circles or drawing as tools to show your answer.)
- What should you include in your answer so that someone else will understand your thinking? (You can use words to explain you answer and then use drawings and labels as examples that make your answer clear to others. You can use examples and counter examples to help Josh understand your thinking.)
Use Check-In: Questions 16–20 in the Student Guide and the corresponding Feedback Box in the Teacher Guide to assess students' progress toward recognizing that the same fractional parts of different-sized unit wholes are not equal [E4] and identifying the unit whole when given a fractional part of a whole [E7].
Check-In: Question 20 can also be used to assess students on the following Math Practices Expectations:
- MPE2.
- Find a strategy. I choose good tools and an efficient strategy for solving the problem.
- MPE5.
- Show my work. I show or tell how I arrived at my answer so someone else can understand my thinking.
