Welcome to "Probe Path Jump", a Grade 2 Add/Subtract on a Number Line mission at the Explorer core practice level, staged in a space scenario. The mission opens with a hands-on prompt: "Start at 18. Make 6 hops of size 5. Place the END on the number line." Students work with the numbers 18, 6, 5 and reach a final answer of 1 across 3 guided steps.
Behind the story, this lesson builds add/subtract on a number line understanding aligned to CCSS 2.MD.B.6. The key strategy is: 18 + 30 = 48.
A common misconception this page surfaces is: Jumping in the wrong direction for subtraction. Plus = right (toward bigger). Minus = left (toward 0). Picture the arrow before the first hop. The adaptive Socratic hints move from a small nudge to a fuller strategy, keeping the reasoning visible for students, parents, and teachers.
Grade 2 · Add/Subtract on a Number Line
Mission Progress
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Thinking Summary · 1
Mastered[object Object]
[Discovery] Start at 18. Make 6 hops of size 5. Place the END on the number line.
1
Active StepPlace the marker on 48.
Everything you need to know about the Socratic experience.
Start at 18. Make 6 hops of size 5. Place the END on the number line. Hint: Each hop adds +5. From 18, take 6 hops.
Starting from 48, how many MORE hops of size 5 reach 50? If you get stuck, the adaptive hint is: 2 ÷ 5 = 1.
Explorer missions hit the core abstraction at typical numeric ranges — this is where conceptual mastery is built. Within Grade 2 Add/Subtract on a Number Line, expect numbers in the corresponding range.
Jumping in the wrong direction for subtraction. Plus = right (toward bigger). Minus = left (toward 0). Picture the arrow before the first hop.
Add/Subtract within 100 (The number-line view is a second representation of the same arithmetic.) 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.
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.
