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Day 19 · Equal totals can hide different constraintsYear 5 Maths · T1 W3–4 · Day 19 lesson

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Year 5 / Mathematics / Term 1 / Weeks 03 04

Part of the full two-week lesson sequence. Check the pack guide and taught point before teaching.

Open for this lesson: Pack guide · Sources and materials · Worked swaps · Aids and text routes.

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Success: formulate and compare two multiplicative plans, then choose the one that meets a stated limit. Prepare: 24×36 versus 32×27 paper-bundle model. Codes: AC9M5N09, AC9M5N06, AC9M5N08.

  1. Recall · 2 min. Ask if equal totals guarantee equal practicality. Key: no; another constraint can differ.
  2. Model · 5 min. Both invented arrangements hold 864 cards: 24×36=864 and 32×27=864. If the fictional workspace allows at most 30 bundles, only 27 bundles fits. Do not invent a price, environmental impact or real policy.
  3. Guide · 6 min. Compare 18×42=756 with 27×28=756 under at most 30 bundles. The 28-bundle arrangement fits; 42 does not. Let children state the multiplication equation and constraint separately.
  4. Choose · 7 min. Day 19 A/B/C route. Require two products, constraint test and a recommendation limited to the supplied facts; a learner may challenge missing information.
  5. Exit · 3 min. “Can we name the cheapest option from these numbers?” Key: no, no prices were given. If a child asserts a cost, ask which source supplies it.
  6. Record · 2 min. Note product, constraint and limit to conclusion as separate evidence. A correct total with unsupported recommendation needs feedback.

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