Goal: represent and compare 111–115, distinguishing 111 from 101. Prepare: hundred square, one strip, five singles, H/T/O mat, Day 26 cards.
- Notice, 3: Put models of 101 and 110 beside each other. Ask what each extra piece is worth.
- Model, 5: Make 112 as 100 + 10 + 2. Point to the 1, 1 and 2 in their H/T/O columns. Put a model of 102 beside it to show that the extra full ten changes the total by ten.
- Guided, 8: Cards A/B show 111 and 114. Build or select both models, match numerals, and compare their equal hundred and ten pieces before comparing singles.
- Independent, 6: Card C shows 115. Learner makes it and changes it to 113 without moving the hundred or ten. Give a large H/T/O mat if digit writing obscures the reasoning.
- Exit, 3: Ask for the numeral one hundred + one ten + three ones and one more. Key: 113 and 114. If 103 is named, place the ten-strip in view and ask which column records it.