Standards: 5.NBT.1, 5.NBT.3, 5.NBT.4 · Place value and decimals to thousandths, ×10 and ÷10 relationships

Part 1 — Zoomable number-line city (blocks → streets → houses → rooms, each level 10× finer, with an address readout) plus the Power-of-10 Elevator: digits slide past a bolted-down decimal point, equation shown with exponents, and a “basement limit” message when ÷10 would need ten-thousandths.
Part 2 — 8 lock-in rounds mixing comparison duels (targets the longer-is-bigger and more-digits-is-bigger traps, plus 0.800 = 0.8) and rounding rounds, each revealed on a number line zoomed to the first differing place or the halfway point.
Part 3 — Expanded Form Machine (place-value table, expanded form, number name with “and”), Power-of-10 Machine (floor-by-floor slides), Rounding Machine (landmarks → halfway → decide, with the “5 or more” rule explained as a shortcut for “past halfway”).
Part 4 — 10-question quiz, tiers: City Planner / Street Surveyor / House Inspector / New Arrival.

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