Codes: AC9M3N05. Target: estimate a collection, group-count it and judge the estimate. Set out: the teacher's sealed clear container of 47 identical large paper counters or an accessible tray; count and record the true amount before class.
- Invite · 3 min. Show the container briefly. Say: “Without opening or counting each piece yet, what is a sensible estimate? Give a reason, such as ‘more than 30 but less than 60’.” Keep estimates private initially.
- Model a benchmark · 4 min. Show a separate visible group of ten counters. Say: “I can compare the container with this ten. I think there are several tens.” Do not reveal 47.
- Revise a guess · 6 min. Let children view from another angle. They write/select an interval and one estimate, then decide whether to revise. Ask: “What new observation changed your thinking?” An estimate is allowed to differ from the exact count.
- Count by groups · 7 min. Adult opens the container at a controlled desk; pairs organise into tens and singles or the teacher moves pieces at a child's direction. Count 4 tens and 7 singles = 47. If opening is inappropriate, use an adult-recorded video-free sequence of pictures or prepared tactile groups and note the change of evidence route.
- Compare · 3 min. Ask: “Was your estimate near 47? Was your interval wide enough? What would help next time?” Do not score precision alone; a reason and revision matter.
- Brief check · 2 min. Show 18 counters for 5 seconds. Everyone estimates
about 20and gives a comparison with 10. Focus learners explain. Recount together after collecting responses.
Access: large visible tokens, tactile ten bundles after the first estimate, private number selection or AAC. Keep counters away from mouths; use paper squares too large to be a choking hazard under local policy.