Goal: state Card A's round:square ratio with labels and compare each part with the whole. 25 = 2 + 5 + 6 + 7 + 5.
- 0–2: Show three round and two square paper pieces. Ask, “Which group does the first 3 count?”
- 2–7: Model round:square = 3:2. Say “three round for every two square,” then count five altogether. Draw a boundary between part-to-part
3:2and part-to-all3:5. - 7–13: Learners physically or visually swap the order: square:round = 2:3, while the total stays five. Ask each to point to the named first group.
- 13–20: Routes: move labelled round/square tokens on the order mat; draw two labelled rows and write both ratios; speak/type/AAC “first group : second group” and give the five-token check. All routes identify which comparison was made.
- 20–25: Exit “If I say square:round, why is 3:2 wrong?” Key: the first number must count squares, so 2:3. Move: underline the first named group before writing any numbers.
Alternative domains: invented poster icons or repair-kit cards. Optional/home: sketch a fictional 4 stars and 1 line, name both ratio orders; no collection from home. Two more cases.