Author note — to cover

Find the nth term of an increasing linear sequence: the common difference becomes the coefficient of n, the constant adjusts from the first term, e.g. 4n − 1; stress it is a formula in n, never the rule add 4. Decreasing cases are the sibling; quadratic nth terms are Higher. Both tiers. (A25)

• Fluency — direct questions on the nth term of a linear sequence, 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).