Percentage Change Formula and the History of the Percent Sign
How to calculate percentage change correctly, why +50% then −50% is not zero, and where the percent sign came from.
Math Articles
Guides and formula histories for our math calculators.
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Square Roots: Babylonian Clay Tablets to Your Calculator
A 3,700-year-old tablet already knew √2. Here is how square roots work and how machines compute them.
Theoretical Yield and Electronegativity: Two Chemistry Calculations Explained
Two core chemistry calculations, with the history behind them and worked examples.