Codes: AC9M2N01, AC9M2N02. Goal: independently represent an unseen three-digit number, rename it and explain the role of zero. Prepare: closed Day 20 learner check, bundles, staff key.
- Invite · 2. Say, “Your models will show me what to teach next. You may use bundles, a sketch, words or numerals.”
- Model · 5. Rehearse 251 only:
2H 5T 1O = 1H 15T 1O. Count one exchanged hundred as ten tens. Hide this example before checks. - Guided · 6. Still with 251, invite the class to reverse the exchange and explain why the amount remains 251. Revisit zero place using 320, not either check number. Do not reveal check prompts.
- Held-out independent · 6. Give the student check. Children answer items 1–2 without partner assistance; adult reads wording neutrally and records any mathematical prompt.
- Held-out exit · 4. Children answer items 3–4. Retain work before feedback. Finish privately later if access time is needed rather than treating an unfinished item as an error.
- Note · 2. Use the rubric and next moves by item. D20 practice choices follow the check later.
Access/home/extension: Child can direct an adult to move pieces, point to place labels, use AAC or dictate a check sentence. Home choices are practice and do not replace a teacher-observed independent sample. Extension after the check: demonstrate a third equivalent grouping and use a number line to estimate position.