Codes: AC9M2N01, AC9M2N02. Goal: distinguish 206, 260 and 26; rename one hundred as ten tens. Prepare: mat, number cards, 10 ten-strips that can become a hundred-sheet.
- Invite · 2 min. Show
206and26. Say: “They use the same 2 and 6. What does the zero do?” Collect two hypotheses. - Model · 5 min. Build 206: 2 hundreds, no tens, 6 ones. Then build 26: no hundreds, 2 tens, 6 ones. Say: “The empty tens place in 206 cannot just vanish.” Contrast 260 with 2 hundreds, 6 tens, no ones.
- Guided rename · 6 min. Exchange one hundred-sheet for ten ten-strips without changing quantity. Say: “206 is 2 hundreds, 0 tens, 6 ones. It can also be 1 hundred, 10 tens, 6 ones.” Count the tens together; record
2 × 100 + 6 = 100 + 10 × 10 + 6. Ask what stayed the same. - Sort and explain · 7 min. In pairs match the cards
206, 260, 26to three builds. One explains the zero position; partner checks with place labels. Add a non-standard challenge: make 260 as 26 tens. - Use it · 3 min. Read a “supply cabinet” note: “2 hundreds, 6 tens, 0 singles.” Children write/select 260 and explain why it cannot be 206.
- Check · 2 min. Everyone selects the build for 206 among two. Focus learners identify the empty column. If confusion remains, revisit place labels before bigger numbers.
Access routes: clear text labels; tactile empty-column marker; wide-spaced numerals; adult moves groups on instruction. Do not use colour alone to encode place.