Welcome to "Tray Bundle Swap", a Grade 2 Regrouping within 1000 mission at the Explorer core practice level, staged in a bakery scenario. The mission opens with a hands-on prompt: "Trade sugar cubes to add 437 and 285. First, build 2 bundles of 10 sugar cubes (a stand-in for the hundreds in 285)." Students work with the numbers 437, 285, 2 and reach a final answer of 2 across 3 guided steps.
Behind the story, this lesson builds regrouping within 1000 understanding aligned to CCSS 2.NBT.B.7. The key strategy is: 437 + 285 = 722.
A common misconception this page surfaces is: Trying to borrow from a zero in the tens place. A 0 in the tens place must first borrow from the hundreds — chain the unbundle: 1 hundred → 10 tens → then lend. The adaptive Socratic hints move from a small nudge to a fuller strategy, keeping the reasoning visible for students, parents, and teachers.
Grade 2 · Regrouping within 1000
Mission Progress
0/3
Thinking Summary · 1
Mastered[object Object]
[Discovery] Trade sugar cubes to add 437 and 285. First, build 2 bundles of 10 sugar cubes (a stand-in for the hundreds in 285).
1
Active StepDistribute items equally among groups
Everything you need to know about the Socratic experience.
Trade sugar cubes to add 437 and 285. First, build 2 bundles of 10 sugar cubes (a stand-in for the hundreds in 285). Hint: 285 has 2 hundreds. We sketch them as 2 bundles of 10.
How many column regroups (carries or borrows) did this addition require? If you get stuck, the adaptive hint is: Required regroups: 2.
Explorer missions hit the core abstraction at typical numeric ranges — this is where conceptual mastery is built. Within Grade 2 Regrouping within 1000, expect numbers in the corresponding range.
Trying to borrow from a zero in the tens place. A 0 in the tens place must first borrow from the hundreds — chain the unbundle: 1 hundred → 10 tens → then lend.
Add/Subtract within 100 (Two-digit fluency is the substrate for three-digit regrouping.) Open /grade-2/addsubwithin100 to start that topic's missions.
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.
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.
