Mixed Facts Within 20 is a free printable Grade 1 maths worksheet on switching operation item by item, aligned to Common Core standard 1.OA.C.6. It prints 16 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.
Set 1 of 25 · the same problems every time you open this link.
Next set1.OA.C.6
Work out each answer.
LessonPrint · 1.OA.C.6 · Set 1 · free to copy for classroom use
Set 1. Prints on its own sheet.
It practises switching operation item by item — 16 questions for Grade 1, all on Common Core 1.OA.C.6: Add and subtract within 20, quickly and accurately within 10. The instruction to pupils is “Work out each answer”, and the answer key follows on the next sheet.
CCSS.MATH.CONTENT.1.OA.C.6 — 1.OA.C.6, in the Operations & Algebraic Thinking domain for Grade 1. The published standard reads: “Add and subtract within 20, demonstrating fluency for addition and subtraction within 10.” The worksheet assesses that standard rather than a paraphrase of it.
Mixed Facts Within 20 is written for Grade 1, typically ages 6-7. It is one of the sheets on 1.OA.C.6, so it suits any pupil working at that standard — including older pupils revisiting it and younger ones working ahead.
Yes. All 16 answers are generated from the same problems as the questions, so the key cannot drift out of step with the sheet. It starts on a fresh sheet of paper, after the questions, so it is not handed out with the class by accident.
25 — one per pupil, and all 25 ask different questions. Set 1 downloads the whole class as a single PDF. Every version is fixed to its own address, so a sheet printed today holds the same problems when you reopen it next week.
Yes. Mixed Facts Within 20, its answer key and its 25 versions are free to print and photocopy for your own class, with no account, no email capture and no subscription at the download step. Please do not resell them or republish them as your own.
Add and subtract within 20, quickly and accurately within 10.
Last reviewed 2026-09-05. Aligned to 1.OA.C.6 of the Common Core State Standards for mathematics.