Author note — to cover

LCM from prime factorisations, taking every prime to its higher index; why the LCM is at most the product and equals it only for coprime numbers; listing multiples as backup. Worded HCF-or-LCM decisions live on choosing-hcf-or-lcm. Both tiers. (N4)

• Fluency — direct questions on lowest common multiple, 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).