Goal: use the cost base to calculate a fictional mark-up and selling price. 25 = 2 + 5 + 6 + 7 + 5.
- 0–2: Show Card J's $80 stated unit cost and 25% mark-up on cost. Ask which number supplies the percentage base.
- 2–7: Model
$80×0.25=$20gap and$80+$20=$100stated selling price; reverse check$100−$80=$20. - 7–13: Learners estimate 25% as one quarter of $80 and explain why
25% of $100would answer a different question. - 13–20: Routes: place four equal cost-quarter strips on the base grid; annotate base/gap/price boxes; write or dictate
price=cost×1.25and reverse subtraction. All routes name omitted tax and other costs. - 20–25: Exit “Is the $20 proven net profit?” Key: no; extra costs are omitted. Move: separate mathematical unit price gap from a business net-profit conclusion.
Alternative domains: fictional game-event badge or community theatre prop. Optional/home: model a made-up $40 base with 10% mark-up; no purchase. Two optional swaps.