Author note — to cover

Cover reverse percentage after a decrease: divide the sale or reduced value by the decrease multiplier, refuting the add-the-percentage-back shortcut with a numeric counterexample. Sale price and depreciated value contexts, single step only. Increases are the sibling page; multi-year decay with powers of the multiplier belongs to Growth and decay. Both tiers. (R9)

• Fluency — direct questions on the original after a decrease, limited to this lesson's stated scope (4 questions).
• Application — use the same skill in unfamiliar or contextual questions without introducing a later method (4 questions).
• Check — questions built around the exclusions and likely misconceptions named in the lesson brief (4 questions).