Author note — to cover

Factorise x² + bx + c into two brackets from a pair summing to b and multiplying to c, covering all sign cases: c positive with b negative, c negative, and b zero pointing to the difference-of-squares page. Coefficient a > 1 is the Higher sibling; solving the equations is the equations topic. Both tiers. (A4)

• Fluency — direct questions on factorising a quadratic expression, 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).