Turn It Around — Adding to 20
1.OA.B.3
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LessonPrint · 1.OA.B.3 · Set 12 · free to copy for classroom use
Turn It Around — Adding to 20 is a free printable Grade 1 maths worksheet on commutativity across ten, shown as a pair, aligned to Common Core standard 1.OA.B.3. It prints 9 questions with an answer key on its own sheet of paper, in 25 versions that each ask different questions, so no two pupils in the class work from the same page. Print it from the browser or download it as a PDF — no account, no email.
1.OA.B.3
Fill in both blanks.
LessonPrint · 1.OA.B.3 · Set 12 · free to copy for classroom use
Set 12. Prints on its own sheet.
Use facts you know to work out ones you do not — like knowing 3+8 because you know 8+3.
Teaching this next? Using Known Facts to Add is the 40-minute plan for it, with the misconceptions to expect.
Last reviewed 2026-09-05. Aligned to 1.OA.B.3 of the Common Core State Standards for mathematics.