Grade Range: 4-6

ACF Lesson Plan: Math:
How Much Do We Use?


Students examine how much electricity costs in different states and how much it costs to power different devices in their home.

Download  PDF version of this lesson.




Students will:

  1. Use data to generate charts and graphs
  2. Draw conclusions using the data

National Standards:

  • CCSS.MATH.CONTENT.4.MD.A: Solve problems involving measurement and conversion of measurements.

Time Needed:

Two class periods


  • Internet access


Day One:

  1. Begin by asking students all of the different ways we get our electricity. Be sure they mention coal and other fossil fuels as well as renewable sources like solar, wind, water, etc.
  2. Then ask them how much they think electricity costs. How is that measured?
  3. Direct them to this website that lists of cost of electricity per state:
  4. As a whole group, show the students how to read this table, and that there are different rates depending on if the electricity is used by a residence, a company, for industrial purposes, or by transportation.
  5. There are several ways this data can be used to generate a bar graph. One bar graph generator can be found here:
  6. Discuss the required information for the bar graph. What information should be on the x axis? The y axis? What is a good title? What units of measurement are required? Guide them to set up their graph properly.
  7. Using the column for the residential rates for the most recent year available, have them locate the 10 states that have the lowest cost of electricity. A reminder about reading decimals might be needed.
  8. Have students generate a bar graph for the 10 states with the lowest cost of electricity.
  9. Then, show them the bar graph (the second one on this website): Compare the states with the lowest cost of electricity with the states that use the most coal to generate their electricity. Discuss the correlations the students notice.

Day Two:

  1. Review the lesson from yesterday.
  2. Today, students will look at data about use of energy by various devices:
  3. Have students choose 5 devices that they use in their daily life. Use the energy calculator to estimate the number of hours each day they use that device, then calculate the amount of electricity used. They should make a list of the 5 devices and the cost, including the unit. The calculator will give you the option of Cost Per Hour, Cost Per Day, Cost Per Month, Cost Per Year, or kWh Per Day. You will want to choose one and have them use that consistently across their devices for a consistent comparison.
  4. Then show them the pie chart generator: Discuss how to set it up correctly.
  5. Have the students input the data for the devices they chose.
  6. Once their pie chart is generated, they should interpret them by answering questions like these:
    • Which device uses the most electricity? Why?
    • Which one uses the least? Why?


Students’ ability to interpret the data in the graphs/charts they create should be measured. Choose questions from the lesson and have students answer in writing.


  1. After exploring the electricity usage calculator more, have the students share the different costs for each device and reasons they might be different.
  2. Students might also explore this infographic:
  3. Questions to ask include:
    • What percentage of your state’s total electricity generation comes from coal?
    • What other sources of energy does your state produce electricity from? Are any of them greater than coal?
    • How can you explain the differences between the states in terms of electricity generation? What do these numbers tell you about the resources available in a particular state?
    • Create other questions like these and share them with a partner. Answer each other’s questions.
  4. Students might also recalculate the lesson using past years’ data.


Students in need of support might work with smaller amounts of data, or with mixed ability groups.