Percent Change

Up, down, and back again

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

• Up p% means × (1 + p/100). Down p% means × (1 − p/100). Successive changes multiply.
• Percent change is always measured from the old value.
• To undo a discount, divide by the multiplier: −25% needs +33.3% to recover.

Steps

1. Up then down
2. Multipliers
3. Which base?
4. Undo a discount
5. Sale price
6. Price rises