Fractions of a set
Given a visible group, identify or compare the part named by a basic fraction while preserving the same whole set.
Surface
Fractions of a set uses short visual tasks with clear answer actions and repairable mistakes.
Selection
Fresh independent work can move toward Core, Transfer, or Challenge routes; help use or confusion keeps support visible.
Help
Hints keep attention on the visible structure; reveals show the path without counting as independent evidence.
Presentation
Presentation can reduce reading and interaction load without changing the selected skill. Practice focus can bias compatible work without breaking prerequisites or story fit.