Two-Digit Addition Within 100 — Free Grade 2 Practice in Orbit

The station's oxygen code scrambled mid-orbit and rebuilding it takes two-digit addition — the regrouping kind, where 53 + 65 crosses a hundred and the tens column has to carry. Two of the four clue stations lean on this: one asks for the answer on a number line, the other sends it past as a moving asteroid. Same math, two different demands. Second grade is where addition is supposed to become fluent rather than effortful, and fluency needs volume more than it needs novelty.

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What this station asks for

🛰️ Plot the CourseWelcome aboard, Cadet. Starlight Station has gone dark and its oxygen code was scrambled on purpose — by one of the crew. First, fly us there: solve each addition and slide your rocket to the exact number to lock the course. You work out the answer, then slide the rocket along a number line to set the course. Five tasks, then the flight log goes into the Case File.
☄️ Through the Asteroid BeltGreat flying! A belt of asteroids blocks the docking bay. Work out each answer, then blast the asteroid showing that exact number. Sharp eyes, Agent! You solve each problem and tap the drifting space rock that carries the answer. Five tasks, then a boot print goes into the Case File.

Five questions it might ask

Drawn from the same pool the activity uses, so these are the real thing rather than an illustration. The numbers change on every attempt — there is no fixed set to memorize.

Question	Answer
59 + 60 = ?	119
47 + 13 = ?	60
71 + 10 = ?	81
61 + 15 = ?	76
25 + 50 = ?	75

👀 What to watch for

Regrouping errors cluster in one place: the child adds the ones, writes the whole two-digit result, and never carries. On the number line this shows up as an answer that's ten short. Asking them to estimate first — "is it more or less than 100?" — catches most of it.

The Common Core standard behind it

Official wording, quoted in full — not our summary of it:

2.NBT.B.5	Fluently add and subtract within 100 using strategies based on place value, properties of operations, and/or the relationship between addition and subtraction.

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Other Grade 2 skills in this case

Subtraction within 1002.NBT.B.5 Two-step word problems2.OA.A.1

All grades

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