## Summary

Students will explore the purchasing power of the half dollar. Students will collect and graph prices over time, and then write math problems to determine the percent increase between periods.

## Objectives

• Students will demonstrate an understanding of purchasing power and the changes in costs of goods over time.
• Students will practice organizing and plotting data and reading graphs to find trends.
• Students will determine the percent increase of costs for a given product and write related mathematical problems.

• Math

• 3rd
• 4th

## Class Time

• Total Time: 46-90 minutes

## Lesson Steps

Discuss Half Dollar and Key Concepts (15 minutes)
1. Start this lesson by reviewing the types of coins students may be familiar with. Ask students to share which coins they have used or have seen. If no one mentions the half dollar, ask students if they have seen one before. Explain that today they will see two different designs used on the half dollar, one that is used today – the Kennedy Half Dollar-- and one that was used more than 60 years ago—the Franklin Half Dollar.
2. Hand out the Half Dollar Power Graphic Organizer. Ask students to fill in their organizer during the discussion. Display images of the Franklin and Kennedy half dollar (see last page of the organizer for images). Explain that these coins are worth 50 cents and can be used to purchase goods, but they are also common for collecting. Tell students we are going to find out which of these half dollars could buy more goods during the time period the coins were made.
3. Explain to students that we are going to investigate how much purchasing power the half dollar has. Using chart paper, whiteboard or other method, create two columns. Title one side 50 Cents. Ask students to think about what they could buy for 50 cents today and write the students answers underneath 50 cents. If they need some help, here are a few ideas you can share: pencils, gumballs, bulk candy, lemonade from a lemonade stand, or a postcard.
Research Costs of Goods Over Time (45 minutes)

## Differentiated Learning Options

• Allow students to work in pairs or small groups to complete the chart and graph.
• Work as a class to complete the graphic organizer and price research.
• Use an online graph tool.
• Allow students to use calculator to determine the percent increases.
• Introduce the concept of a percent decrease and ask students if there were any decades when the prices decreased and by what percentage.
• Generate percent increase problems together and solve them as a class.
• Pick 2-3 decades and ask students to determine how many half dollars they would need to pay for their goods.

## Assess

Observe students' graphic organizers and graphs to determine if they've met the lesson objectives.

## Common Core Standards

CCSS.MATH.CONTENT.3.MD.B.3 Draw a scaled picture graph and a scaled bar graph to represent a data set with several categories. Solve one- and two-step "how many more" and "how many less" problems using information presented in scaled bar graphs. For example, draw a bar graph in which each square in the bar graph might represent 5 pets. CCSS.MATH.CONTENT.4.MD.A.1 Know relative sizes of measurement units within one system of units including km, m, cm; kg, g; lb, oz.; l, ml; hr, min, sec. Within a single system of measurement, express measurements in a larger unit in terms of a smaller unit. Record measurement equivalents in a two-column table. For example, know that 1 ft is 12 times as long as 1 in. Express the length of a 4 ft snake as 48 in. Generate a conversion table for feet and inches listing the number pairs (1, 12), (2, 24), (3, 36), CCSS.MATH.CONTENT.4.MD.A.2 Use the four operations to solve word problems involving distances, intervals of time, liquid volumes, masses of objects, and money, including problems involving simple fractions or decimals, and problems that require expressing measurements given in a larger unit in terms of a smaller unit. Represent measurement quantities using diagrams such as number line diagrams that feature a measurement scale.

## National Standards

This lesson plan is not associated with any National Standards.