Author note — to cover

Cover the meaning of direct proportion, multiplying one quantity multiplies the other by the same factor, with scaling-factor solutions for cost, mass and length problems and 'is directly proportional to' language. Stress constant ratio, not merely both increasing. The unitary method, graphs and y = kx each get their own page. Both tiers. (R10, R7)

• Fluency — direct questions on direct proportion, 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).