Author note — to cover

Cover the closed form, final amount equals principal times the multiplier to the power n: identifying principal, rate and n from wordy questions, decimal-rate care (2.5% gives 1.025), and interest earned versus final balance. Finding n belongs to finding-how-long; extracting an unknown rate by nth roots leans Higher and should be flagged as such. Both tiers. (R16, R9)

• Fluency — direct questions on the compound interest formula, 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).