Target/codes: count each piece once to 16 and explain why the same set still has 16 after rearrangement; AC9MFN01, AC9MFN03. Prepare: P153 sixteen identical broad tiles, count-once mat; no spare tile on the work surface.
- Notice · 3 min. Show ten and six paper-gallery tiles. Ask “What would let us know the amount without guessing from the shape?”
- Model · 4 min. Move each of the first ten into a counted place, then each of the six, saying one number word per piece. Point to the last word, sixteen, as the answer to “how many”.
- Guide · 5 min. Child/directing adult returns the same sixteen tiles to an irregular cluster, checking none was added or removed. Child selects a tracking path before recounting.
- Independent route · 7 min. Choose Day 153 A/B/C in a gallery, paper garden or sign-table story. Require stable total,
16numeral and a reason about unchanged pieces. - Evidence check · 4 min. Ask “Would the number change if we made a longer row?” Move pieces without changing count. Record whether the child's reason refers to count or only appearance.
- Exit · 2 min. Child names or points to the last counted word and one way to avoid a double count.