# Skill variation ladder
Skill: [prealg.expression-manipulation.expand-factorise](/math/skills/prealg/expression-manipulation-expand-factorise)
Family: Equations, Variables, Expressions, and Inequalities
Algebraic expression manipulation: simplify, expand, factorise variation ladder grows by changing representation, numeric range, constraint count, distractors, language load, and transfer context.
## AXIO levels
- 6. Advanced enrichment: Reason about the general method or a non-routine variant.
- 5. Challenge extension: Combine the skill with a second idea, hidden constraint, or explanation requirement.
- 3. Core task: Solve the target skill independently.
- 1. Foundation recognition: Notice the relevant quantity, shape, relation, or constraint before calculating.
- 2. Guided strategy: Use a visible scaffold, model, or narrowing move to choose a valid next step.
- 4. Transfer form: Apply the same idea when numbers, wording, or representation changes.
## Hints and Checks
- Decision restated without adding a new method.
- Common slip nudge: Treating grade, year, source family, or contest label as level.
- One useful scaffold after help is requested.