Percentage Traps

Read the numbers carefully

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Relative change (a percentage) differs from absolute change (the actual amount).
• Differences between percentages are measured in percentage points.
• Percentages of different bases can’t be averaged; always check the base and sample size.

Steps

1. Doubled risk
2. Points vs percent
3. Averaging percentages
4. Price including tax
5. Up, then down
6. Survey of 10