Lesson 2: Exponential Growth & Decay

• What is exponential growth?
• What is exponential decay?
• How do we identify the growth/decay factor?
• What does the base tell us about growth or decay?

Growth, decay, growth factor, decay factor, rate, doubling, halving

CCSS.MATH.9.F.LE.A.1, CCSS.MATH.9.F.LE.B.5

Description: Students explore exponential growth (where the base > 1, so values increase) and exponential decay (where the base is between 0 and 1, so values decrease). They identify growth/decay factors and write exponential functions to model real-world situations. Purpose: To develop understanding of how exponential functions model real-world growth and decay. DOK Level: 2-3 (Application)

• Real-world contexts: Population, bacteria, radioactivity, investments
• For struggling learners: Use simple growth factors (2, 3) and decay factors (0.5)
• For advanced learners: Explore various growth/decay rates
• Table and graph: Show growth/decay both numerically and visually

• Observation: Can students identify growth vs. decay?

• Worksheet: Create exponential functions for growth/decay scenarios

• Table task: Create input/output tables for growth/decay functions

• Application: Solve a real-world growth/decay problem

• Real-world growth/decay context cards

• Growth/decay factor identification guides

• Practice worksheets

• Input/output table templates

• Resource: Khan Academy "Exponential Growth & Decay" (adapted)