Financial Mathematics
Plain-English math for interest, APR, amortization, minimum payments, and opportunity cost—with clear assumptions.
- How credit card interest is calculated
A plain-English walkthrough of APR, daily periodic rates, average daily balance methods, and why issuer agreements matter.
12 min · intermediate
- Daily periodic rates explained
What a daily periodic rate is, how it relates to APR, and how to read it without overclaiming compounding.
8 min · foundational
- Compound interest: when it helps and when it hurts
How compounding can grow savings—and how interest on debt can expand balances when you pay slowly.
10 min · foundational
- Inflation and interest rates: the basics
How inflation and interest rates relate in everyday life—prices, borrowing costs, and savings—without investing jargon overload.
10 min · foundational