Author note — to cover

P(not A) as 1 minus P(A) in fraction, decimal and percentage forms, with wording such as does not rain, and spotting questions where the complement is faster. Both tiers. Exclude at-least-one questions across repeated trials (Combined events topic) and formal complement notation with Venn diagrams (set-notation, Diagrams topic). (P4)

• Fluency — direct questions on the probability of an event not happening, 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).