What Is a Loan? Principal, Interest & Terms

Why this matters

Borrow $6,000 and a lender can walk away with $7,200 once it is paid off, a difference most students never expect until Marcus Bell's real car loan spells it out in front of them. Every loan carries that hidden second number, and this lesson makes students calculate it instead of accepting a monthly payment at face value.

The trade-off I push hardest is the one buyers get wrong most: a longer term drops the monthly payment but raises the total interest, so a smaller number on paper stops looking like the better deal once students run it themselves. By the time they compare two competing offers, they're defending a recommendation with math, not a gut feeling about which payment looks easier.

From one teacher to another

I built this around one number students have to sit with before anything else clicks: a $6,000 loan can actually cost $7,200 to pay off, and that gap is the whole lesson. Working through Marcus Bell's real car-loan numbers, students calculate the interest themselves using principal times rate times years, then divide the total repaid by the number of months to find his own monthly payment. The part I push hardest is the term trade-off, because it's the single most useful idea in the unit: they stretch the same $6,000 loan across three different terms and calculate, on their own, how far the monthly payment drops and how much the total interest climbs, so a smaller monthly number stops looking automatically like the better deal. They also work out why Marcus's loan counts as secured, naming the car itself as the collateral the lender could take, and connect that directly to why an unsecured loan like a credit card usually charges more. The closing task hands them two real competing loan offers and asks for an actual recommendation, not a summary, so they have to pick a side and defend it with their own calculated numbers.