Author note — to cover

Define events that cannot both happen on one trial and test stated pairs for exclusivity with a justification, such as odd and prime sharing 3. Contrast with independence, the classic confusion. Both tiers. Exclude the addition rule itself (or-rule page) and intersection notation (set-notation, Diagrams topic). (P4)

• Fluency — direct questions on mutually exclusive events, 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).