Author note — to cover

Substitute positive integers, simple decimals and fractions into expressions in one or two letters, applying the order of operations, e.g. 3a + 2b or 5(x − 2). Boundaries: negative inputs and squared terms have their own sibling pages; formulae in context sit on substituting-into-formulae. Both tiers. (A2)

• Fluency — direct questions on substituting into an 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).