Author note — to cover

Write (x + 4)² as (x + 4)(x + 4) and expand fully, killing the x² + 16 error; include (x − a)² and coefficient cases like (2x + 3)². State the pattern a² + 2ab + b² as a check rather than a shortcut. Both tiers. (A4)

• Fluency — direct questions on squaring a bracket, 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).