Welcome to "Donut Tray Stacker", a 1st Grade Tensadd mission at the Challenger (stretch) level, staged in our bakery scenario. The mission opens with a hands-on prompt: "First batch: 2 trays of 10 cookies (20 cookies). Second batch: 8 more trays of 10 (80 cookies). Build BOTH batches as ten-bundles." You'll work with the numbers 2, 10, 20 and arrive at a final answer of 110 across 3 guided steps.
Behind the bakery story, this lesson is really about tensadd aligned to CCSS 1.NBT.C.4. Add multiples of 10 within 100 — when you add tens, the ones digit never changes. The key strategy this mission asks you to internalise: Adding tens is just like adding ones — but each unit is worth 10.
A general pattern to watch for in 1st Grade tensadd — illustrated with example numbers below, which may differ from this lesson's: Forgetting the trailing zero (e.g., 30 + 40 = 7). 3 tens + 4 tens = 7 TENS, not 7 ones. The unit must travel through the answer. If you get stuck on "Donut Tray Stacker", 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 1 · Tensadd
Mission Progress
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Thinking Summary · 1
Mastered[object Object]
[Discovery] First batch: 2 trays of 10 cookies (20 cookies). Second batch: 8 more trays of 10 (80 cookies). Build BOTH batches as ten-bundles.
1
Active StepDistribute items equally among groups
Everything you need to know about the Socratic experience.
First batch: 2 trays of 10 cookies (20 cookies). Second batch: 8 more trays of 10 (80 cookies). Build BOTH batches as ten-bundles. Hint: Tap "+ Add Group" 10 times. Each group gets exactly 10.
One more bundle of 10 cookies arrives. What is the new total now? If you get stuck, the adaptive hint is: 100 + 10 = ?
Challenger missions push beyond CCSS expectations with edge cases that surface deeper misconceptions. Within 1st Grade Tensadd, expect numbers in the corresponding range.
Adding 30 + 40 by counting all 70 ones individually. Treat the ten-bundles as countable objects in their own right. Skip-count by 10s, not by 1s.
Place Value (Adding tens IS place value in motion — the tens column drives the change.). Open /grade-1/place-value 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.
