Shop 'Til You Drop: Food for Thought

A lesson plan by Julia L. Meyer - Notre Dame High School St. Louis, MO

Subject: Mathematics and Home Economics - Grade 6-8
Duration: 5 class periods

This lesson plan was one of the winners in a lesson plan contest sponsored by TeachersFirst in 2002. TeachersFirst editors have added technology options where appropriate.

Rationale Text activities presented on meal planning and other consumer math-related items are often too basic and outdated. Students need a more interactive, hands-on activity that is both fun for them and a creative outlet.
Objectives Students will:
  1. Locate items in a virtual grocery store.
  2. Calculate the unit price for items and determine the best buy.
  3. Calculate the tax and total grocery bill.
  4. Use coupons and sale items to save money.
  5. Plan a well-balanced meal.
  6. Shop on a limited budget.
Applicable Standards
Materials Internet access, web resources for online grocery shopping and grocery coupons, paper copies of coupons (provided in the Sunday paper), paper copies of grocery sale flyers (optional)
Resources and technology options Online grocery sites:
You can use a local store or select one from a collection of online grocery sites reviewed here. If you aren't sure which stores in your area provide online shopping services, assign students to find out as a homework assignment! If you want a wider variety of choices, use Google to search online groceries.

Online coupon sites:
Check your local grocery chains for their own online coupon sites or...You can search on Google, but many are so cluttered with ads they would confuse their own designers. These few are not too bad:
Cool Savings - Grocery Coupons
Smartsource Coupons

Tools to electronically "present" the final project meal plan and grocery receipts
(your choice will depend on your students' prior experience with these tools and availability of computers for them to use):
  1. Use Excel or Google Docs spreadsheet ((reviewed here) for the grocery list and receipt. This option is for teacher and students who have prior experience with spreadsheets or you will need to extend the time and add a lesson on how to make a spreadsheet.
  2. Share the meal plan via PowerPoint with images of ingredients (consider using Flickr -- reviewed here -- and their advanced search to find those with Creative Commons licensing so copyright is not an issue). Alternatives to PowerPoint include Google Docs presentations (reviewed here) or the online tool, SlideRocket.
  3. Make the meal plan into an interactive "book" or web page, using images taken with a digital camera (of real food) or from Flickr (see above). Of course students will need to include text to explain their menu, etc. Interactive books can be made with Bookemon (reviewed here). Visually-rich web pages can be made using TRintuition workBench (reviewed here).
  4. Use a class wiki to share the menu plans and spreadsheets. As you conduct this project from year to year, students can see examples from past years and even compare the prices over time. If you don't want them to see TOO much, you can temporarily "hide" wiki pages from previous years, then reveal them after your students finish their presentations. For more information about wikis, see TeachersFirst's Wiki Walk-Through.

Tip: Most schools do not permit student email access for middle school level students. If yours does, ignore this tip! If the tool you choose requires an email address, use a teacher email or set up Gmail sub-accounts under a single teacher account. Here is a blog post that tells how to set up GMail subaccounts to use for any online membership service.
Day 1 Introduce students to a web site that allows consumers to shop for groceries online (your choice from above or a list of options shared via your teacher web page)

Students should register for the home shopping club/service by entering a fictional name, password for shopping, address, etc. Make them record their username, password, etc and turn it in to you in case they forget!

Tip: Most schools do not permit student email access for middle school level students. If yours does, ignore this tip! If the site requires an email address, use a teacher email or set up Gmail sub-accounts under a single teacher account. Here is a blog post that tells how to set up GMail subaccounts to use for any online membership service.

Next, have students browse the virtual grocery store. (Instruct them to find their favorite ice cream under frozen foods or a gallon of milk under dairy.) Make sure students visit the meat department. Explain that meat can be ordered according to weight but that they might not get that exact weight depending on the selection. Therefore, the cost is approximate.

Students should choose items for their shopping cart by indicating the quantity and submitting the items as they leave each department. At this point, there is no limit to the amount students may choose.

Students should then check out and, while doing so, print a list of items that is given at the end, as well as the total cost. Using this subtotal, students should determine the tax, if applicable in your state, at the appropriate rate. (e.g., 6.5%). Student also need to add the delivery fee and determine their new total.

Discuss as a class the advantages and disadvantages of shopping using the Internet. Have students compare totals to see who was frugal and who was extravagant.

Optional: Have students keep a spreadsheet of their purchase using Excel or Google Docs spreadsheets (reviewed here). This would allow them to compare and use formulas for later assignments.
Day 2 Discuss unit price, that is, total cost divided by total quantity. (e.g., if apples are 4 for $1, then they are $.25 each; if juice is $1.65 for 10 ounces, then it is $.165 per ounce.)

Students should log onto the grocery store web site and find a sale item (usually indicated in different color.) Introduce paper sale flyer if desired. As a class, compare a sale item's unit price to a generic or store brand to determine the better buy. If you have in interactive whiteboard, display the web page and your calculations on the whiteboard--having students do the work. If you are using a spreadsheet, set up formulas to calculate unit price for any item you enter.

Students will find 3 to 4 items that are available in differing quantities. They will record price and quantity and determine the unit price. Then they should indicate which is the best buy for each item. Again, a spreadsheet would provide a record for easy comparison.
Day 3 Pass out 2 to 3 coupons to each student or have them print from your selected coupon site. Discuss expiration date and double coupons (and those not permitted to be doubled). Have students log onto the grocery store web site and find the items for which they have coupons. (Note: Students will discover that not all items are available at that particular store.) Have students shop for coupon items and check out. Since the web site does not take into account coupons, students should calculate their discount, tax and new total. They can do this on paper or in their spreadsheet.
Days 4 & 5 Give students instructions and time to work on the final project. The project will consist of students planning a well-balanced meal for 4 to 6 people. Well-balanced means the meal should include a meat/protein item, a fruit or vegetable item, a starch or bread item, a beverage, and a dessert. (No microwave dinners or pizzas!) However, each student must not spend more than $50. Students are required to use at least 2 coupons. If students find that they are still under budget, they may shop for bonus items (which will be worth extra credit, since this indicates a student has cut costs!)

The student will then present his or her project in two parts. The first will consist of a printout of the shopping list with an attachment which includes the computation of discount, tax, delivery fee, and total. The second part is a visual presentation of what is included in the meal or shopping cart. This can be in "hard copy," i.e. a poster or in electronic form. See resources for tools to make electronic versions.
  • Introductory Shopping List (5 points). Graded only for participation.
  • Unit Price Activity (15 points). Graded for correctness of computation.
  • Coupon Activity (10 points). Graded for correctness of computation.
  • Project:
    • (10 points for being within budget.)
    • (10 points for being well-balanced.)
    • (2 points for each additional item beyond original meal.)
    • (20 points for correctness of computation.)
    • (30 points for creativity of presentation.)

More TeachersFirst resources for middle school Math, FCS