Are you looking for a way to make exponential functions relevant for your students? Over the next three Math Mondays, we’ll cover how to use NGPF’s MATH activities to teach exponential growth, decay, and compounding interest with real-world applications. 

In today’s math activity, students will learn to calculate the exponential growth of different investments using the formula y = ab^x. Check it out in MATH: Exponential Growth in Investments or view the MATH Collection here. 

The Activity: Using the Edpuzzle video and example problem, students learn how to set up and solve exponential equations from word problems. Then, they practice evaluating how much different investments will be worth after a number of years. 

Finally, students solidify their learning through reflection and application. They graph and compare how an investment would grow, depending on the initial investment amount, and give financial advice to a friend. 

Building Engagement and Conceptual Understanding: Here are some fun ways you can supplement this activity to differentiate and deepen math learning.

• Build conceptual understanding by introducing exponential functions with the Desmos activity Avi and Benita’s Repair Shop. 
• Add a kinesthetic component with the Rice and Chessboard Problem, explained and adapted here with a fun vampire twist. Students place one piece of rice on the first square of a chessboard, and double the amount on each following square. 
• Give students a piece of paper and ask “How many times would you need to fold this paper to reach the moon?” Check out this video for inspiration. 
• One final puzzle - the Tower of Hanoi! Students try to move rings from one side to the other in the fewest moves possible. Hint: it follows an exponential pattern!
• Blend math, reading, and whimsy by teaching from The Number Devil by Hans Magnus Enzenberger, a book for middle schoolers where Robert, a boy who hates math, explores mathematical concepts through fantastical adventures led by the Number Devil. 

Extend the Personal Finance Learning: If you’re a math teacher, use these resources to further explore investing and make real-world connections to exponential growth. 

• INTERACTIVE: Invest with STAX (NGPF)
• INTERACTIVE: The Power of Compounding (NGPF)
• FinCap Friday: The Raging Bull (NGPF)

For Your Learning: Check out our new On-Demand MATH PD on Compounding Interest. Tune in for the next two Math Mondays, which will cover exponential decay and compounding interest. 

About the Author

Kathryn Dawson

Kathryn (she/her) is excited to join the NGPF team after 9 years of experience in education as a mentor, tutor, and special education teacher. She is a graduate of Cornell University with a degree in policy analysis and management and has a master's degree in education from Brooklyn College. Kathryn is looking forward to bringing her passion for accessibility and educational justice into curriculum design at NGPF. During her free time, Kathryn loves embarking on cooking projects, walking around her Seattle neighborhood with her partner and dog, or lounging in a hammock with a book.