1.OA.C Addition within 20 Worksheet (Set A) — Grade 1

About this worksheet

Common Core standard 1.OA.C: Add and subtract within 20.

This printable practice page focuses on Addition within 20, a core skill in the Grade 1 Operations & Algebraic Thinking strand. It is laid out in a clean single-column format that prints on a standard letter-size sheet. Use it as a do-now, an in-class practice page, an exit ticket, or take-home homework. For more on this skill, see our classroom guide to teaching Addition within 20.

Worked Example

4 + 3 = ___

Solution. Start with 4. Count up 3 more: 5, 6, 7. The total is 7.

Answer: 7

Practice Problems — 1.OA.C

Name: ______________________ Date: __________

7 + 11 = ___
19 + 1 = ___
3 + 3 = ___
13 + 1 = ___
2 + 16 = ___
11 + 7 = ___
6 + 12 = ___
15 + 1 = ___
2 + 4 = ___
12 + 6 = ___

Answer Key

How to use this in class

Print one copy per student on standard letter-size paper. The page is sized so a student can complete it in roughly 14 minutes of focused work. If you are pacing a 45-minute math block, this page works well as a do-now while you take attendance, as guided practice after a 10-minute mini-lesson, or as an end-of-class exit ticket. For small-group instruction, project the page on your board, work the first item together as a think-aloud, then have students complete two more independently while you confer. Pair this page with a concrete-pictorial-abstract progression when introducing the skill for the first time.

How to use this at home

Sit beside your child rather than across from them. Read the standard description above out loud once before they start. Resist the urge to correct as they go — let them finish the page, then circle two or three items you want to revisit together. Most parents find that one printable a day, three or four days a week, is enough to keep a child fluent without making math feel like a chore.

Standards alignment & what comes next

This page is aligned to Common Core standard 1.OA.C in the Operations & Algebraic Thinking strand for Grade 1. The skill connects upward to later-grade work in the same strand and downward to the prerequisites students should have already mastered. If your district uses a different framework, the standard text above will help you map this page into your scope-and-sequence document. For deeper background on the standard's progression, see the Common Core Math Standards progression document.

Teacher / Parent Note

The questions here are randomly seeded from a deterministic generator, so each standard's worksheet is unique but reproducible. If you reload the page you will see the same problem set — perfect for printing the same copy for an absent student a week later. Difficulty: Practice.