Codes: AC9M2N04, AC9M2A02. Goal: solve 28 + 5 using a ten bridge and explain the split. Prepare: 10-frame, two ten-strips and ones.
- Invite · 2 min. Say: “28 is close to a new ten. How many ones fill it?” Invite finger/counter answers.
- Model · 5 min. Make 28 as 2 tens and 8 ones. Move 2 of the 5 new ones to complete 30; 3 remain. Say and write
28 + 5 = 28 + 2 + 3 = 33. Point out 5 was split into 2 and 3, not doubled. - Guided example · 6 min. Solve 47 + 6 together: 47 needs 3 to reach 50; 3 remain; answer 53. Learners show the split with fingers or counters and say why both parts total 6.
- Partner attempts · 7 min. Try 36 + 7 and 59 + 4. One partner builds/marks tens, the other explains and checks by counting on or reversing with subtraction. Answers: 43 and 63. If a learner is still learning facts to 20, use 8 + 5 first with the same bridge.
- Context · 3 min. “A shelf has 28 paper sheets and gets 5 more. What does 33 mean?” Learners state the unit and check whether 33 is reasonable.
- Check · 2 min. Everyone solves 18 + 4 with a marked split. Focus learners show
2 + 2, total 22. If a learner writes 14, rebuild 18 before asking them to explain.
Access routes: ten-frame and paper groups, high-contrast split marks, enlarged numerals, AAC explanation or adult scribe. Do not require mental speed as the only evidence of strategy.