Day 17 · A zero still holds a placeYear 3 Maths · T1 W3–4 · Day 17 lesson

Code: AC9M3N01 (partial). Goal: distinguish similar five-digit numerals and preserve zero-place meaning after regrouping. Prepare: 30 507, 30 570, place mat.

1. Invite · 2. Show both numerals. Ask, “Which counts are different? Which first place decides?”
2. Model · 5. Read 30 507 as 3TT 0Th 5H 0T 7O. Point to empty thousands and tens. Compare 30 570 = 3TT 0Th 5H 7T 0O: equal through hundreds; tens decide that 30 570 is larger. Exchange one TT in 30 507 to 2TT 10Th 5H 0T 7O and check total.
3. Guided · 6. Sort 40 205, 40 250, 42 005 least to greatest using the first differing place; learners point to each zero's place. Ask whether changing the zero's position changes the count.
4. Choice · 6. Choose D17-A/B/C. Child builds or sketches place cards and explains which place decides an order.
5. Exit · 4. Compare 50 080 with 50 008; expect 50 080 larger because 8 tens exceed 0 tens after the earlier places tie. If a child sees only the final 8, realign cards by place.
6. Note · 2. Record whether reading, ordering, or exchange needs reteaching.

Access/home/extension: Large spaced numerals and tactile empty-place tokens; home may use paper place names. Extension: write a different numeral between 30 507 and 30 570 and justify.