Fraction Fun by David A. Adler

Mathematical Strand:

Number and Operation

Topic:

Students will develop strategies for adding and subtracting fractions. Students will search for and generalize patterns.

Grade level:

4th - 6th grade

Lesson Created by:

Joy Heinrichs Theodore Roosevelt Elementary, Manhattan, KS

Lesson Description

Materials

• Book Fraction Fun by David A. Adler, graph paper, rulers, pencils, square paper for a model pizza, paper (or blank transparency to share chart with class), overhead projector
  

1. Launching the lesson

1. What are some ways you use fractions in everyday life? (Pie, pizza, recipes, etc.)
   
2. Read the book
   

2. Exploring the lesson

1. Pretend our class made a huge square pizza for our upcoming class party. We made it a week in advance and kept it in the cafeteria freezer. Much to our dismay, a Pizza Thief found out. That night, he disguised himself as a custodian, tiptoed into the cafeteria, and gobbled down half our pizza! On the second night, he ate half of what was left of our pizza. Each night after that, he crept in and ate half of the pizza that remained! When we went to cook our pizza for the party, we were shocked by what we found!
   
2. Pose the question: What fraction of the pizza was left for the party?
3. Let groups of 3 or 4 work together to find a solution.
   
4. Also find: The fraction of the pizza the Pizza Thief ate each day. The fraction of pizza he had eaten so far at the end of each day. The fraction of the pizza that remained at the end of each day.
   
5. Have the students make a chart (on a transparency) to organize their data
   
6. As they work, suggest they make a diagram or use a square paper as a model
   

3. Summarize/Discussion/Elaboration

1. Have a group show their chart on the overhead projector
   
2. What patterns do you see?
   
3. The amount eaten each day is a fraction with denominator 2 times as large as the one before.
   
4. Can anyone explain for us why this pattern works?
   
5. Each day the Pizza Thief is taking ½ of the piece that is left, so he’s dividing the leftover piece into 2 pieces
   
6. Other pattern: In the "Total amount eaten" column, each fraction has a denominator 1 greater that the numerator and the denominators are powers of 2.
   
7. Students could graph the total amount eaten so far for each of the 7 days and a graph of how much pizza remains at the end of the day for each of the 7 days. Compare the 2 graphs.
   
8. Teacher can visually represent this problem by cutting a square paper in ½., for the 1st night, cut that in ½ for the 2nd night, and so on, labeling the pieces.
   

Other fraction books that could substitute: Eating Fractions by Bruce McMillan, How Do Octopi Eat Pizza Pie? By Time Life for Children