1st grade addition within 20 worksheets

First graders add within 20 using strategies like counting on, doubles, and making a ten. These sheets stack the facts vertically so your child sees the same layout they'll use for bigger numbers later.

Free printable PDF worksheet, aligned to Common Core 1.OA.C.6.

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The kind of problems you'll get

Solve each problem. Write your answer on the line.

8 + 2 =
Answer: 10
1 + 10 =
13 + 7 =

Every print pulls a fresh set of problems at this level, so a make-up test or a second sibling never gets the same sheet.

What's on each sheet

Fluency. Solve each problem. Write your answer on the line. 25 questions per page.
Mad-Minute Grid. Solve as many as you can. Write each answer under its problem. 25 questions per page.

Every version prints on US Letter or A4, with its answer key on the last page.

How to teach this

Teach one strategy at a time: counting on, then doubles, then making ten. Have your child say the fact aloud before writing the answer. When fingers come out for 9 + 6, model make-a-ten together: nine and one more is ten, then five left over.

Watch for: Kids count all the way up from one. Start at the bigger number and count on, or make a ten first (9 + 6 is 10 + 5). Kids stall at sums that cross ten. Break the second addend to fill the ten: 8 + 5 becomes 8 + 2 + 3.

Common questions about addition within 20

What addition facts should a 1st grader know?: By the end of 1st grade, kids add fluently within 10 and use strategies like making ten for sums to 20. These sheets practice both ranges.
How many problems are on each sheet?: The 1st grade sheet has 25 stacked addition facts. Every print generates a fresh mix, so no two sheets match.

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Aligned to Common Core 1.OA.C.6. Reviewed by the One more sheet curriculum team. Content version 123, updated July 2026.