Money Math Daily
The math behind everyday money decisions, worked out step by step.
inflation
Inflation, Explained With a Grocery Receipt
How the Consumer Price Index measures rising prices, illustrated with a simple grocery cart example and the math behind purchasing power loss.
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compound interest
The Rule of 72, and Where It Actually Breaks Down
A plain explanation of the Rule of 72 shortcut for doubling time, with the real math showing exactly how far off it gets at higher rates.
credit cards
What a Credit Card's Minimum Payment Really Costs You
The federal rule behind the minimum payment warning on your statement, and a worked example showing how much extra time and interest it adds.
saving
What Saving $100 a Month Really Adds Up To
A plain-numbers look at how $100 saved monthly grows over 10, 20, 30, and 40 years under one assumed, clearly stated rate of return.