Codes: AC9M2N02, AC9M2A01. Goal: rename 134 in standard and non-standard groups, then extend a +10 pattern. Prepare: exchangeable bundles and cards 134, 144, 154, __, 174.
- Invite · 2 min. Build 134 and ask: “Could it still be 134 if I open the hundred bundle?”
- Model · 5 min. Exchange 1 hundred for 10 tens: now 13 tens and 4 ones. Say: “The pieces changed; the count did not.” Record
1H 3T 4O = 13T 4O; count 130 + 4. Explain that 13 tens is a useful non-standard grouping. - Guided exchanges · 6 min. Make 120, exchange its hundred, and have learners say 12 tens. Return to 134; exchange one ten for ten ones to show
1H 2T 14O. Ask how to check the total with objects and a number sentence. - Pattern task · 7 min. Display
134, 144, 154, __, 174. Say: “Tell the rule in words before filling the gap.” Learners add a ten-strip at each step, predict 164 and explain why ones stay 4. Try the reverse pattern174, 164, __. - Use it · 3 min. “A stationery box has 13 packets of 10 and 4 loose pencils. What number?” Learners model or sketch 134; this is a fictional counting context.
- Check · 2 min. Everyone completes
205, 215, __and shows the grouping for 225. Focus learners name what increased. If they write 216, repeat with ten-strips.
Access routes: pre-bundled pieces, partner handling, calculator-free verbal reasoning, high-contrast labels and non-motor response. Keep addition of 10 distinct from adding 1.