Author note — to cover

Expand (x + a)(x + b) in all four sign combinations by grid or FOIL, collecting the two middle terms. Coefficients of x stay 1 here: (2x + 3)(3x − 1) is the sibling page, squaring a bracket its own page, and three brackets the Higher page. Both tiers. (A4)

• Fluency — direct questions on expanding double brackets, 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).