Goal: count and exchange through 70 without losing or inventing objects. Prepare: six strips, ten ones, seventh strip, Day 14 cards.
- Notice, 3: On the chart find 67, 68, 69. Ask what would come next and how a model must change.
- Model, 5: Build 69, add one, exchange ten ones for the seventh strip. Display 69 + 1 = 70 and 7 tens + 0 ones. Audit before/after by counting tens as 10, 20…70.
- Guided, 8: A (postcard exhibition: six rows of ten cards plus seven) and B (trail model: six groups of ten stepping marks plus nine) are 67 and 69. Learners count on from 67 to 70 with three single moves; after each move, name the full total, not just the ones.
- Independent, 6: C (garden design: seven printed strips of ten leaf icons) shows 70. Learner makes an equivalent unexchanged form of six strips plus ten icons and explains why both are 70. Offer large marks or tactile strips.
- Exit, 3: Ask for one more than 69 and one less than 70, with a model. Key: 70 and 69. If the answer is 610, trade ten ones and ask for the number of full tens.