Welcome to "Croissant Angle Sum", a 4th Grade Anglesum mission at the Seedling (entry-level) level, staged in our bakery scenario. The mission opens with a hands-on prompt: "The whole angle is 90° and one part is 75°. Rotate the orange ray to show the unknown part." You'll work with the numbers 90, 75 and arrive at a final answer of 105 across 3 guided steps.
Behind the bakery story, this lesson is really about anglesum aligned to CCSS 4.MD.C.7. Recognize angle measure as additive. The key strategy this mission asks you to internalise: Unknown = 15°.
A general pattern to watch for in 4th Grade anglesum — illustrated with example numbers below, which may differ from this lesson's: Forgetting that a straight line is 180°. A straight line forms a 180° angle. Adjacent angles on a line always sum to 180°. If you get stuck on "Croissant Angle Sum", 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 · Anglesum
Mission Progress
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Thinking Summary · 1
Mastered[object Object]
[Discovery] The whole angle is 90° and one part is 75°. Rotate the orange ray to show the unknown part.
1
Active StepRotate the orange ray to align with the blue target at 15°.
Everything you need to know about the Socratic experience.
The whole angle is 90° and one part is 75°. Rotate the orange ray to show the unknown part. Hint: Both parts together add up to the whole. Subtract: 90 − 75.
Two angles share a ray and together form a straight line. If one is 75°, what is the other? If you get stuck, the adaptive hint is: Supplementary angles sum to 180°.
Seedling missions anchor the visual model with small, friendly numbers — ideal as the first attempt at this topic. Within 4th Grade Anglesum, expect numbers in the corresponding range.
Multiplying angle measures instead of adding them. Angles compose by ADDING. Two 30° slices side by side make 60°, not 900°.
Angles (Measuring is the prerequisite for adding.). Open /grade-4/angles 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.
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.
