Teacher copy: This page may include teaching prompts or answer keys. Answer keys in this public library can be viewed by anyone. Give learners a clean prompt, use checks as formative evidence, and change a case locally when prior access matters.
Target: distinguish movement along, inside and beyond a fixed PPF and quantify one trade-off. Prepare: Cards A/F and frontier aid.
Launch · 2 min. Compare F1 (2,9) with F2 (3,6). Ask if the move creates capacity.
Model · 4 min. Both are on the old frontier. Moving F1→F2 gains one workshop and forgoes three circles. It is a choice along, not an outward shift. (2,6) is inside; (3,9) exceeds the model's current maximum.
Guided reading · 5 min. Compare 0→1 workshop (one circle forgone) with 2→3 (three circles forgone). Ask why a single constant opportunity cost would misread this table.
Practice route · 7 min. Choose Day 7 route; classify F's three proposals and annotate one computed cost with units.
Audit · 4 min. Partner calls inside point “unemployment proven.” Learner narrows to underuse in the model; a specific cause cannot be inferred.
Exit · 3 min. “From 3 workshops to 4, how many circles are forgone?” Key: 6−0=6 circles, conditional on Card A.