Students explore food prices and how they have changed over time as they perform mathematical computations, analyze data charts, and compare and contrast statistical information. Grades 3-5

commodity: a primary agricultural product that can be bought and sold

farmer: person who owns or manages a farm, cultivates land or crops, or raises animals

retail food prices: the cost of food at a grocery store or other retail outlet

This lesson includes information on how food price data can be used to make mathematical computation practice interesting and informative. Review the materials and revise them to meet the needs of your students.

You may choose to customize the lesson to include current and past newspaper grocery ads. Consider comparing commodity prices from one season to the next and from one year to another. Statistics and colorful graphs are available from a variety of sources. 

As you use this lesson, it is important for students to realize that the United States has the safest, most abundant food supply in the world. Most farmers do not make a lot of money producing the food Americans consume. In fact, people who farm most often do it because they have a passion for it. Today, over 90% of farm families have some income that comes from outside of farming.² Profit made in agriculture is most often accrued on the marketing end. It may be interesting for your students to meet a producer and learn about his/her operation.

1. Choose a food item and write the steps from farm production to consumption on the board from left to right.  For example:
   • Milk is produced by cows on a dairy farm; a truck picks the milk up and takes it to a processing plant; the milk is processed and packaged into butter, yogurt, and other dairy products; finally the product is transported to grocery stores where it is purchased and consumed.
   • Eggs are produced by chickens on a farm. Next, the eggs are cleaned, packaged and checked for quality at a processing plant. Finally, the eggs are transported to grocery stores where they are sold to consumers.
2. As students visualize the different steps of the production of their food, help them understand that the food is sold on each level. When they buy food at the grocery store they are paying the farmer to produce it, the processor to prepare it for consumption, and the grocery store for putting it on their shelves.
3. Ask the students, "What costs are associated with purchasing food at the grocery store?"

1. Review the Reading Chart I and II activity sheets. If necessary, rewrite the activity sheets or create math problems that supplement them.
2. Introduce your students to the lesson by having them think about the prices their family pays for specific food items and how they think that price is determined. Possible discussion and/or writing prompts are listed below.
   • If you were to ask your parents if the price of food is going up or down what would they say?
   • On average, is it less expensive, more expensive, or about the same to eat at a restaurant than at home? Explain.
   • How do you think the price of food is determined?
   • Do the farmers who grow the crops make a lot of money on the food you are eating?
   • If you were to compare the price of food in the United States to the price of food in other countries, would it be more or less expensive?
3. Introduce your students to the Average Prices of Foods—Retail chart. In general, discuss what the chart shows. Review the meaning of average.
4. Have the students complete the student activity sheets and the homework assignment. Part of the homework assignment requires students to make a graph. Be sure they have the rough drafts of their graphs approved before preparing their final copies.
5. Share the graphs the students have created. Display the student graphs in the library, hallways, grocery stores, and at special events such as parent meetings and open houses.

After conducting these activities, review and summarize the following key concepts:

• The cost of buying food pays for the production of the food on the farm, the processing or packing of the food, as well as the work of the grocer who sells it.
• The cost of food changes as years pass and also from season to season.

1. Food and Farm Facts
2. http://www.ers.usda.gov/webdocs/publications/eib117/40008_eib-117_summary.pdf

• Food and Farm Facts Booklet
• Tuttle's Red Barn: The Story of America's Oldest Family Farm