The delicious shape shop - project idea in teaching math

A consumer-math-skills project that students K-8 will eat up

Here's a project idea that works at any grade level to teach a variety of math skills and concepts in a fun and motivational way. Follow these steps to help your class set up and operate their own "Delicious Shape Shop."

1. MAKING SHAPE MODELS

Begin by helping students use pretzel sticks and gumdrops to create physical models of geometric shapes, like those pictured above. Simple two-dimensional shapes, such as triangles and rectangles, can be created by elementary students, while more complex three-dimensional shapes, such as triangular prisms and pyramids, are appropriate for middle schoolers. Provide guidance in identifying such attributes as the number of sides, edges, faces, and vertices, using The Greedy Triangle, by Marilyn Burns (Scholastic, 1994), as a read-aloud and reference.

2. START A SHOP

Propose the idea of running a school shop to sell these shapes. Engage students in a discussion on shopping with such questions as "When have you gone shopping?" " What did you buy?" "How did you know that you were given the right change?"

3. COUNTING COSTS AND PRICING

Before opening your shop, decide on the respective monetary values of a pretzel rod and a gumdrop. Students can then calculate the total cost of each shape using addition, skip counting, or multiplication. For example, if a pretzel stick is worth 2 cents and a gumdrop is worth 1 cent, then a triangle made of three pretzel sticks and three gumdrops is worth 9 cents (2+2+2+1+1+1 = 9[cents]). For more challenging division and decimal work, ask older children to count the pretzel sticks or gumdrops per package and divide the purchase price of the bag by this amount, to come up with the actual cost per item. For example, you might purchase a package of 20 gumdrops for 50 cents. By dividing 50 cents by 20, students can determine that each gumdrop costs about $0.025, or 2 1/2 cents.

Inform students that most stores charge a certain amount more than they actually pay to make or to buy the product wholesale. This extra amount is a store's profit, also called a mark-up. This is how stores make money.

4. SETTING UP SHOP

Once shapes have been created and priced, have the class name them. Tantalizing Triangles? Scrumptious squares? Captivating Cubes? Setting up the store will provide many creative opportunities for kids to connect with math - as poster artists, advertising writers, clerks, shop designers, marketing experts, and more.

5. USING MONEY AND MAKING CHANGE

Make sure to provide plenty of change and boxes in which to keep money organized. Practice money-counting and change-making skills beforehand by running a play store with kids taking turns as clerks.

If you have a computer with a CD-ROM drive, Math Shop Deluxe and Math Shop Jr. (Scholastic) make excellent practice materials. Younger students will enjoy working as bank clerks in Math Shop Jr., and older students can assist customers in Math Shop Deluxe, making the right amount of change and calculating bills.

6. PROFITS AND DEBRIEFING

Finally, the shop opens and is a great success. But were there any profits? Using the original purchase prices you decided upon, have the class check costs versus total money collected. The class might contribute any profits to a worthy local cause or buy new classroom math materials.

To reinforce the real-world connection, have students reflect on their experience and write a list of the different kinds of math they used in running the shop and creating the products. With their eyes wide open to all the math that's involved in buying and selling at any store they visit, for these young entrepreneurs, shopping will never be the same!

Bob Krech has been an educator for 21 years. More Project Problems[TM] like this one are available in his book Special Delivery: Putting Math to Work (Cuisenaire, 1998).

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