Welcome to "Pastry Inventory Lab", a 4th Grade Multidigitmult mission at the Explorer (core) level, staged in our bakery scenario. The mission opens with a hands-on prompt: "Decompose 18 × 12 into place-value parts and fill each cell of the partial-products box." You'll reason about the numbers 18, 12 across 3 guided steps.
Behind the bakery story, this lesson is really about multidigitmult aligned to CCSS 4.NBT.B.5. Multiply a whole number of up to four digits by a one-digit number, and multiply two two-digit numbers, using strategies based on place value. The key strategy this mission asks you to internalise: 18 × 12 = ?
A general pattern to watch for in 4th Grade multidigitmult — illustrated with example numbers below, which may differ from this lesson's: Misaligning partial products before summing. Use graph paper or column lines. Partial products live in different place-value columns and must stack accordingly. If you get stuck on "Pastry Inventory Lab", the adaptive Socratic hints below escalate from a gentle nudge to a worked-out strategy — the same way a one-on-one tutor would coach you through it.
Grade 4 · Multidigitmult
Mission Progress
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Thinking Summary · 1
Mastered[object Object]
[Discovery] Decompose 18 × 12 into place-value parts and fill each cell of the partial-products box.
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Active StepDecompose 18 × 12 into place-value parts. Fill each cell, then sum.
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Everything you need to know about the Socratic experience.
Decompose 18 × 12 into place-value parts and fill each cell of the partial-products box. Hint: Break 18 into tens + ones, 12 into tens + ones, then multiply each pair.
Does 12 × 18 give the same answer as 18 × 12? If you get stuck, the adaptive hint is: Same factors, same product, regardless of order.
Explorer missions hit the core abstraction at typical numeric ranges — this is where conceptual mastery is built. Within 4th Grade Multidigitmult, expect numbers in the corresponding range.
Forgetting the place-holder zero on the second row of the standard algorithm. The second row is multiplying by *tens*, not ones — always tag it with a 0 in the ones column first.
Longdivision (Inverse partner — division uses the same place-value strategy in reverse.). Open /grade-4/longdivision to start that topic's missions.
Pure discovery is inefficient — kids hit a wall and quit. Guided Discovery scaffolds the path: a careful sequence of questions, models, and adaptive hints leads the learner toward the insight without revealing it. Inquiry AI's hint system fires automatically after ~15s of hesitation or on the first mistake, escalating from a Socratic nudge to a worked example only when needed. Mistakes are diagnosed via "misconception keys" so the hint matches the actual wrong-thinking pattern.
Inquiry-based learning starts with a question, not a formula — students explore, hypothesize, and verify before being told the rule. In Inquiry AI, every mission opens with a "Discovery" step (manipulate the model), then "Abstraction" (write the equation), then "Reflect" (apply to a new case). The procedure is never given upfront; learners derive it from their own observations.
