Goal: quantify the same 15 objects in two arrangements. Proposed codes: AC9MFN01, AC9MFN03. Prepare: C2, Card 147.
- Retrieve · 3 min. Count a known 10 with child-chosen tracking; ask what makes the last word the total.
- Model · 4 min. Lay 10 and 5 broad tiles; deliberately touch one twice, notice the mistake, then recorrect with indexed places.
- Guide · 5 min. Child counts C2 once and directs moving five into a ring, keeping every tile visible.
- Independent check · 7 min. In book repair, maker display or paper show, child tells whether 15 is still 15 after rearrangement, demonstrating with one-to-one matching or recount.
- Check · 4 min. Hide one tile under a blank cup after announcing a change; ask what must be checked before claiming still 15. Return tile and recount.
- Exit · 2 min. Record whether child used tracking, remembered conservation without evidence, or retested.