0–4 orient: Show cancel in the gallery sign and ask learners to name each percentage's base before calculating. 4–9 source read: Trace $40 cost → marked price → discounted price. 9–16 model: Add 25% of $40 = $10 to reach $50, then subtract 10% of $50 = $5 to reach $45. Ask why $45 is neither $40 nor a 15%-of-$40 shortcut. 16–27 route: Learners show a two-stage receipt, proportional bars or a read-aloud script with both bases and a revised sign. 27–32 audit: Partners underline the exact base beside each percentage and test the phrase returns to cost. 32–35 exit: Collect $45, the two bases and a bounded correction. Give fresh Check B after the lesson if scheduled; use its public key only after the learner's first response.
Teacher evidence log: day | source wording identified | numerical rule and units | source-bound revision | access route | exact help given | next move. Keep this locally and without real child data in shared/public examples. A route choice or time taken does not rank a learner. The QCAA mapping is a partial skills encounter, not a school sequence or certified result.
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