Welcome to "Hidden-Asteroid Recovery", a 1st Grade Inverseops mission at the Challenger (stretch) level, staged in our space exploration scenario. The mission opens with a hands-on prompt: "Build TWO groups: 6 orbiting satellites and 7 docked satellites. Together they make the WHOLE." You'll work with the numbers 6, 7, 13 and arrive at a final answer of 7 across 3 guided steps.
Behind the space exploration story, this lesson is really about inverseops aligned to CCSS 1.OA.B.4. Understand subtraction as an unknown-addend problem — addition and subtraction are two views of the same fact. The key strategy this mission asks you to internalise: 7 + ? = 13. The "?" is what 13 − 7 equals.
A general pattern to watch for in 1st Grade inverseops — illustrated with example numbers below, which may differ from this lesson's: Thinking each equation is a separate fact to memorize. Show that 3 + 5 = 8 and 8 − 5 = 3 are the SAME story — the only difference is which piece is hidden. If you get stuck on "Hidden-Asteroid Recovery", 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.