Author note — to cover

Cover reverse percentage after an increase: divide the final amount by the increase multiplier to recover the original, with VAT, pay rise and population contexts, plus a re-applying check. Non-calculator cases with 20% and 25%. Decrease versions and classifying forward against reverse are the sibling pages; depreciation over years is Growth and decay. Both tiers. (R9)

• Fluency — direct questions on the original after an increase, 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).