Five in-depth guides covering the math of percentages, the common mistakes, and where this stuff shows up in your day-to-day life.
Three reliable methods, the four classic question types, and mental shortcuts for common percentages.
Every percentage formula in one printable reference, plus conversion tables.
The single distinction that causes the most confusion in business and news.
Stacked discounts, asymmetric changes, weighted averages — the typical pitfalls.
Where percentages show up: money, shopping, health, sports, and news literacy.