Standards: 5.NBT.2, 5.NBT.5, 5.NBT.6, 5.NBT.7 · Multi-digit multiplication and division; decimal add/subtract/multiply/divide

Part 1 — The Bulk Order: area model and standard algorithm side by side; each press lights up one partial product in both at once, and the algorithm row shows the running piece until its strip is complete. Crate Splitting: partial-quotient division where each batch is a strip of the rectangle, with a multiplication check at the end.
Part 2 — The Register: 8 sales, each with an estimate gate before the exact total. Ten-times-off distractors trigger the “$2,000-apple alarm”; other distractors target adding-instead-of-multiplying, misaligned decimals, and dividing the wrong way.
Part 3 — Multiplication Machine (estimate → rows with the “why the 0” explanation → add → check), Division Machine (estimate → friendly chunks → add → multiply back), Decimal Register Machine (+, −, ×, ÷ to hundredths: estimate, compute in cents, place the point by decimal-place count and by estimate, check).
Part 4 — Quiz, tiers: Market Manager / Head Cashier / Produce Packer / New Hire.

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