The purpose of this activity is for students to make reasonable estimates about the weight of food waste produced by individuals, by families, and by the school community in a week, a month, and a year. Answers will vary widely, based on the sizes of families, the class, the school, and how much food waste students estimate a person produces in a day. Students use multiplication appropriately in their estimates. When students identify information that they need to know in order to answer a question, consider assumptions about information not given in a situation, model a situation, using a representation such as an equation, and think about the real-world implications of their model, they model with mathematics (MP4).

• Invite students to share their strategies for determining how much food waste they produce per week and other estimates.
• “¿Les sorprendió la estimación de cuánta comida desperdician en un año todas las personas de su escuela?” // “Were you surprised at the estimate of how much food waste everyone in your school produces in a year?” (Yes, I didn’t think we produced that much food waste. No, I’ve seen dumpsters, and they are really large. I thought the amount would be really large.)
• Reveal that the average person in the United States throws out about 349 pounds of trash related to food waste each year.
• “¿Cómo habrían cambiado sus estimaciones si hubieran sabido esto?” // “How would knowing this have changed your estimates?” (If I would have known the average amount, I would have divided to find the amount in a month, then divided again to find the amount in a week. It would not have changed our estimate because we estimated 365 pounds of waste for each person in a year.)

The purpose of this activity is to introduce the food journal that students will use to track the food waste they or their families produce for a week. In this activity, students practice filling out the journal and estimate the weight of what they throw out. To help students develop a sense for the weight of the food waste, consider bringing in a few common food items or images and display their weights in ounces. A few examples are provided below.

Banana: 4 ounces
Cucumber: 7 ounces
Chicken thigh: 2–3 ounces
Small lemon: 2–3 ounces
Carrot: 2 ounces
Medium apple: 6–7 ounces

• Invite a few students to share how they found the total pounds of food waste produced.
• Give each student a food-waste journal.
• “La próxima semana, van a llevar un registro de los desperdicios de comida que produzcan. Anoten qué botaron, por qué lo botaron y su peso estimado, en onzas” // “For the next week, you will keep track of the food waste you produced. Record what you throw out, why you throw it out, and the estimated weight in ounces.”
• “Los científicos recolectan este tipo de información de muchas ciudades y países de todo el mundo. ¿Por qué esta información es útil para ellos?” // “Scientists collect this kind of information for cities and countries all over the world. Why is this information helpful to them?” (To see why people are throwing things out and see how to reduce it. To see how much food waste is going to landfills. To learn what is in food waste and see how that affects the environment.)

The purpose of this activity is for students to analyze their completed food-waste journals. Students begin the activity by sharing their food journal with a partner and discussing a few things they notice. Then they use the data from the journal and their experience with multiplying and dividing large numbers in this unit to estimate how much food waste they might produce in a month and in a year. They compare those results to the national average and discuss some possible reasons for any difference.

• Invite a few students to share how much food waste they will produce in a year and some reasons for any differences between their figure and the national average.
• “Cuando revisaron su diario de desperdicios de comida, ¿qué información les sorprendió?” // “As you looked over your food-waste journal, what information surprised you?” (I was surprised at how much food we threw out. I was surprised that a lot of the food waste was from packaging.)