Welcome to "Asteroid Field Counter", 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 45 × 16 into place-value parts and fill each cell of the partial-products box." You'll reason about the numbers 45, 16 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: 45 × 16 = ?
A general pattern to watch for in 4th Grade multidigitmult — illustrated with example numbers below, which may differ from this lesson's: 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. If you get stuck on "Asteroid Field Counter", 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 45 × 16 into place-value parts and fill each cell of the partial-products box.
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Active StepDecompose 45 × 16 into place-value parts. Fill each cell, then sum.
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Everything you need to know about the Socratic experience.
Decompose 45 × 16 into place-value parts and fill each cell of the partial-products box. Hint: Break 45 into tens + ones, 16 into tens + ones, then multiply each pair.
Does 16 × 45 give the same answer as 45 × 16? 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.
Multiplying only ones × ones and tens × tens (skipping the cross terms). The area model has *four* boxes for a reason. Every digit on top must meet every digit on the bottom.
Factors (Multiplication facts are the raw material for finding factor pairs.). Open /grade-4/factors to start that topic's missions.
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.
Yes. Every mission, handbook page, and topic hub is mapped to a specific CCSS code (visible in the page header). The curriculum follows the CCSS coherence map: Grade 1 number sense → Grade 3 multiplicative thinking → Grade 6 ratio reasoning, with each grade building strictly on the prior year's foundations.
