Mystery Bureau › Grade 2 standards › 2.OA.A.1
📘 Common Core · 2.OA.A.1 · Grade 2
The phrase that makes this standard hard is “with unknowns in all positions.” A second grader who can answer 17 + 14 can still be stopped by “what plus 17 makes 31,” because the second one requires choosing an operation rather than performing one. Two-step problems compound it, since the first answer becomes an input rather than the result.
Quoted verbatim from the Common Core State Standards for Mathematics. Nothing here is paraphrased.
| 2.OA.A.1 | Use addition and subtraction within 100 to solve one- and two-step word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using drawings and equations with a symbol for the unknown number to represent the problem. |
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In plain English: Use addition and subtraction within 100 to solve one- and two-step word problems, with the unknown in any position.
Each one runs in the browser with no account and nothing stored. Five questions apiece.
Real output from the activities above — not written for this page, drawn from the same pools a student gets. The numbers are rebuilt on every attempt.
| Power the reactor to exactly 18 | 18 |
| Power the reactor to exactly 14 | 14 |
| Power the reactor to exactly 44 | 44 |
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