Goal: use zeros and symmetry in Card J, then transfer independently to new Check B. Say: “A factor gives a zero; the graph still needs a check of direction and scale.”
- 0–2: Model solving
(x+1)(x-3)=0for the two roots only. - 2–5: Learners locate the midpoint axis and leave remaining features to explain.
- 5–17: Give Check B, which uses a different downward parabola and new surd. Collect first responses.
- 17–22: Share the public key and ask students to revise one reason, not just a number.
- 22–25: Record which next block is needed: more surd operations, more graph features or both.
Routes: write exact steps and labelled sketch; speak a graph-feature explanation while a partner records coordinates and reasons; place factor/point tiles on a tactile axis then dictate exact results. Other domains: Day 10 swaps are after-check practice. Optional/home: make an invented factored quadratic with roots -2 and 4, then test its midpoint. Move: if a learner uses the midpoint x-value as the turning height, substitute it into the function. Public checks are not secure exams or school assessments.