Addition Within 20 Worksheets

Quick answer: Addition within 20 means adding two numbers whose sum is 20 or less, such as 8 + 7 = 15. This page has 13 free printable addition within 20 worksheets with answer keys for grades 1 and 2. Updated October 2026.

About these addition within 20 worksheets

Once children are comfortable adding within 10, the next goal is every fact up to 10 + 10. These worksheets use addends from 0 to 10 and sums up to 20, the facts that children in the US are expected to know from memory by the end of grade 2.

Facts over 10 are easier with a strategy, so the sheets mix visual models with fact practice: double ten frames show “make 10 and some more”, number lines to 20 show counting on, and dominoes and dice make doubles easy to spot.

Strategies for facts to 20

• Make 10: 8 + 5 is 8 + 2 + 3, which is 10 + 3 = 13.
• Doubles: 6 + 6 = 12, so 6 + 7 is one more, 13. See the doubles worksheets.
• Turn it around: 2 + 9 is the same as 9 + 2, and counting on from 9 is quicker.
• Adding 10: 10 + 6 = 16, the tens digit becomes 1.

Using the worksheets

1. Start with double ten frames and number lines so children see the totals.
2. Move to fact practice pages, first untimed, then as a short daily warm-up.
3. Use the mystery picture, riddle and bingo for review days.
4. Finish with story problems to connect the facts to real situations.

Addition within 20 worksheets: what is in the set

There are 13 addition within 20 worksheets on this page, and every one has an answer key except for the bingo cards. They begin with models that show the totals, and end with fact practice and story problems:

Addition within 20: how many facts are there?

The facts in addition within 20 use two addends from 0 to 10, so there are 121 ordered facts and 66 different ones. Of the 66 different facts, 36 have a sum of 10 or less, and 30 cross ten. These 30 are the new facts that children learn in addition within 20, and this table shows them by sum:

The standard is that children in grade 1 add within 20 (1.OA.C.6), and by the end of grade 2 they know all sums of two one-digit numbers from memory (2.OA.B.2). The Common Core standards for grade 1 operations and algebraic thinking describe both.

Addition facts to 20: which strategy for which fact?

Every one of the 30 facts that cross ten can be solved with one of five strategies. This table assigns each fact to the first strategy that applies, in the order shown, so a child knows what to try first:

Because the strategies cover every fact, there is no need to count. The doubles and near doubles page has worksheets for the doubles and near doubles, and the making 10 page has the make-ten facts.

Sums to 20 worksheets: 12 facts with a strategy

These 12 facts are a sample of the facts that cross ten, with the strategy that works best and the working. Children can cover the last two columns and try to name the strategy first:

Addition facts to 20: adding 9

Facts with a 9 are the easiest to turn into a 10. Add 10 instead, and take 1 back. The table shows eight facts with a 9, and the number line diagram above shows 9 + 6:

Number bonds for addition within 20

Number bonds help children to see addition within 20 as the splitting of a number into two parts. For totals over 10, both parts must be 10 or less, so there are fewer bonds than for totals within 10. This table shows six totals, with the bonds that use two parts from 0 to 10:

For example, 12 has only 5 different bonds with both parts 10 or less (2 + 10, 3 + 9, 4 + 8, 5 + 7 and 6 + 6), and 20 has just one (10 + 10). The number bond worksheets to 20 ask children to find the missing part of a bond like this.

Adding 10 to a number: the easiest facts in addition within 20

Some of the facts in addition within 20 are not hard at all. When one of the numbers is 10, the answer is a teen number, and the tens digit is 1. Children should know these facts first, since they use place value and not counting:

The same idea is the basis for adding 9 and for the make-ten strategy, which is why the sheets with 10 + n are at the start of the fact practice pages.

Addition within 20 with dominoes and dice

The domino and dice worksheets stop at 12, because a double-six domino set and two dice cannot give a bigger sum. This table shows how many dominoes and how many dice rolls give each sum:

Common mistakes with addition within 20

When a fact crosses ten, children make mistakes that they do not make within 10. This table shows what the wrong answers look like for five facts:

A child who writes 10 for 8 + 5 has made the ten but forgotten to add the leftover 3, and a child who counts on from the wrong number is usually one too small. Double ten frames show both mistakes clearly.

Addition within 20 story problems

Story problems show how addition within 20 is used. Ask children to draw the story first, then to write the number sentence and say the answer:

Addition worksheets grade 1: how addition within 20 fits the year

Addition worksheets grade 1 are mostly about addition within 20, and the standard for the year is to add and subtract within 20 using strategies (1.OA.C.6). A typical school year has children finish addition within 10 in the first months, spend the middle of the year on facts that cross ten, and end with addition within 100. The 13 worksheets on this page cover the middle part, so they suit children from about the middle of grade 1 to the start of grade 2.

First grade addition: games and activities for addition within 20

First grade addition is a good time for games, since children are motivated by play. These activities practice the facts that cross ten:

• Double dice: roll two dice, add them, and then add 10 to make a fact within 20. For example, 4 + 3 + 10 = 17.
• Make-ten cards: deal two cards from a pack of the numbers 1 to 9. The player who can say the sum fastest, using make ten, takes both cards.
• Ten-frame race: two players fill ten frames with counters, and the first to say the total of both frames wins the round.
• Number line hop: draw a number line to 20 on the floor and let children hop forward by the second number.
• Bingo to 20: the worksheet pack has bingo boards and calling cards for a whole class.

Support and challenge for addition within 20

For children who need more support: stay with addition within 10 until it is secure, then add 10 + n facts, which are easy, before the other facts. Use two ten frames, and let the child move the counters. Do not rush to timed fact practice.

For children who need more challenge: ask them to find all the pairs that add up to 17, or to add three numbers to 20. The number bond worksheets to 20 and the story problems both give practice with missing numbers.

How to know that a child has learned addition within 20

1. The child chooses a strategy, such as making ten or doubles, and does not count on their fingers.
2. The child can explain how they found 8 + 5.
3. The child knows all the doubles to 10 + 10.
4. The child answers about 20 facts in a minute on the fact practice pages, with at least 90% right.

A five-day plan for addition within 20

Most grade 1 children need a week or two of short sessions to become secure in addition within 20. This plan goes from review to the fact practice pages:

When a child knows these facts, move on to 2-digit addition with regrouping. The whole sequence is on the addition worksheets page, and Wikipedia’s article on addition has more on the history of the operation.

1st grade addition worksheets and first grade addition worksheets

The same pages are searched as addition worksheets for grade 1, first grade addition worksheets, 1st grade addition worksheets, addition worksheets for 1st graders, addition worksheet for grade 1, addition worksheets for grade 1 pdf and addition sheets for 1st grade. All are the free PDFs above, with an answer key on the last page. Parents also ask for adding for 1st graders and addition for 1st grade in general: this is the right page, and the addition hub has the 2nd grade sets.

Addition problems for 1st grade and 1st graders

Addition problems for 1st grade should stay within 20 and use a strategy. Addition problems for 1st graders that use doubles (7 + 7), making ten (9 + 6 is 10 + 5) or counting on are easier to remember than facts learned in order. Use the problem types in the worksheets above, and ask your child to explain how they got each answer.