Author note — to cover

The Venn-diagram method for HCF and LCM of two or three numbers, and HCF x LCM = product for two numbers, including finding a missing number from the other three values. Assumes both prime-factor pages; formal set notation lives in Probability, not here. Both tiers. (N4)

• Fluency — direct questions on hcf and lcm from a venn diagram, 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).