Addition Within 20 — Missing First Number Generator
Free addition worksheet generator for numbers within 20: find the missing first number. Unlimited fresh sheets with answer keys, print or download as PDF.
Grade 1Math1.OA.C.6Answer key included
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Set either number, lock the ones you like.
- #12 + 8 = 10
- #27 + 4 = 11
- #36 + 10 = 16
- #41 + 4 = 5
- #54 + 9 = 13
- #62 + 1 = 3
- #71 + 2 = 3
- #83 + 1 = 4
- #91 + 6 = 7
- #105 + 9 = 14
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Answer key page in PDF
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10 problems · + within 10
Every shuffle deals a brand-new worksheet — free and unlimited, answer key included.
A different sheet every time
Press Shuffle for a fresh set of problems, lock the ones you want to keep, or type your own numbers straight into the list. The answer key is generated from the same sheet you are looking at, so it can never disagree with the questions.
Print straight from the browser or download the PDF — Letter or A4, with or without the key. Nothing to sign up for and no limit on how many you make.