Minecraft
Preparation
Lesson Narrative
In this lesson, students explore the fundamental mathematics of debt. They will examine how the principal amount, the interest rate (APR), and the loan term interact to determine the total cost of borrowing. By the end of the lesson, students will understand that extending a loan term lowers the monthly payment but drastically increases the total interest paid.
Learning Goals
• Analyze the relationship between principal, interest rate, and loan term.
• Calculate total loan costs over different repayment periods.
• Evaluate the trade-off between monthly payment affordability and total interest paid.
Student Facing Learning Goals
• Let's calculate exactly how much extra we pay the bank when we borrow money.
Student Facing Learning Targets
• I can explain how the length of a loan changes the total cost.
• I can define principal, term, and APR.
• I can mathematically prove why a longer loan is more expensive.
Required Academic Standards
National Jump$tart Standards:
• Credit and Debt (Standard 1): Analyze the costs and benefits of various types of credit.
Glossary Entries
Principal: The original amount of money borrowed.
Term: The length of time you have to repay a loan.
APR (Annual Percentage Rate): The annualized cost of borrowing money, expressed as a percentage.
Interest: The fee charged by a lender to borrow money.
Lesson
Warm Up
4.1.1: The Free Money Trap
Launch: Have students stand in randomized groups of 3 at vertical whiteboards. Present the prompt verbally or project it. Give them 4 minutes.
Synthesis: Select two groups to share. Establish the baseline: Lenders make money by charging interest. You are paying for the privilege of getting the money today instead of waiting to save it.
Student Facing Task
A bank offers you $10,000 today to buy a car, but you have to pay them back $12,000 over the next five years. Why does the bank want to give you this money, and what did that $2,000 extra fee actually buy you?
Activity 1
4.1.2: The Term Trap
Launch: Keep students at whiteboards. Project the loan term scenario. Give groups 8 minutes to run the calculations.
Synthesis: Have the class observe the boards. (Teacher Key: 3-year = $900 interest; 5-year = $1,500 interest). Ask: "Why do people usually choose the 5-year loan even though it costs $600 more?" (Answer: Because the monthly payment is lower).
Student Facing Task
You are borrowing $10,000 at a 6% simple interest rate.
• Option A (3-Year Term): Your monthly payment is $304.
• Option B (5-Year Term): Your monthly payment is $193.
1. Calculate the total amount you pay back for Option A (Payment x 36 months).
2. Calculate the total amount you pay back for Option B (Payment x 60 months).
3. Which option makes the bank the most profit?
Activity 2
4.1.3: The Rate Race
Launch: Present the APR scenario. Give the whiteboard groups 8 minutes to calculate the differences.
Synthesis: Facilitate a class debate. (Key: Good credit gets 5%, bad credit gets 15%. The difference over time is massive). Explain how APR acts as a "risk score"—the bank charges you more if they think you might not pay them back.
Student Facing Task
Two friends buy the exact same $20,000 car on a 4-year loan.
• Friend A has great credit and gets a 5% APR. Their total interest is $2,100.
• Friend B has terrible credit and gets a 15% APR. Their total interest is $6,700.
1. How much more did the car cost Friend B in total?
2. Why did the bank legally charge Friend B thousands of dollars more for the exact same car?
Lesson Synthesis
Lesson Synthesis (5 min)
Narrative: Bring the class back to their seats. Review the student-facing learning targets. Summarize: "When you borrow money, you negotiate two things: the monthly payment and the total cost. If you lower one, you raise the other."
Cool Down
4.1.4: The Dealership Pitch
Narrative: This exit ticket serves as a formative assessment on loan term awareness.
Teacher Rubric: A successful response must state that while extending the term from 4 to 6 years lowers the monthly payment, it drastically increases the total amount of interest paid over the life of the loan.
Student Facing Task
A car salesman says, "I know the monthly payment is too high, but if we stretch your loan from 4 years to 6 years, I can get your payment down to exactly what you want!" Mathematically, why is this a bad deal for you and a great deal for the bank?