Welcome to "Probe Production Lab", a 4th Grade Multidigitmult mission at the Challenger (stretch) level, staged in our space exploration scenario. The mission opens with a hands-on prompt: "Decompose 39 × 27 into place-value parts and fill each cell of the partial-products box." You'll reason about the numbers 39, 27 across 3 guided steps.
Behind the space exploration 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: 39 × 27 = ?
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 "Probe Production 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 39 × 27 into place-value parts and fill each cell of the partial-products box.
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Active StepDecompose 39 × 27 into place-value parts. Fill each cell, then sum.
| × 30 | × 9 | |
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| 20 × | ||
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Everything you need to know about the Socratic experience.
Decompose 39 × 27 into place-value parts and fill each cell of the partial-products box. Hint: Break 39 into tens + ones, 27 into tens + ones, then multiply each pair.
Does 27 × 39 give the same answer as 39 × 27? If you get stuck, the adaptive hint is: Same factors, same product, regardless of order.
Challenger missions push beyond CCSS expectations with edge cases that surface deeper misconceptions. 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.
Factors (Multiplication facts are the raw material for finding factor pairs.). Open /grade-4/factors to start that topic's missions.
C-P-A is the Singapore Math sequence proven to deepen number sense: first manipulate physical objects (Concrete), then draw pictures of them (Pictorial), and only then write equations (Abstract). Inquiry AI structures every mission as exactly these three steps — a manipulative, a picture/grid model, and finally the equation. Skipping straight to symbols is the #1 cause of math anxiety; the platform refuses to do it.
Socratic teaching answers a question with a better question. Instead of "the answer is 12", the system asks "if you had 3 groups of 4, how could you skip-count?" The goal is to externalize the learner's reasoning so they hear themselves think. Every Inquiry AI hint follows this pattern: nudge → reframe → analogy → only then a worked example, in that order.
