Classroom · Math · 1st and 2nd grade

Addition within 20 worksheets

A free five-page pack: one strategy with a worked example, problems to count and write, practice with number lines, columns and missing numbers, a fact family, word problems and an answer key.

Download the addition within 20 pack(5 pages, color)Ink saver (B&W)

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Watch it solved

58 sec · with voice and captions

A pencil works one example of each activity, so you can see how the worksheet goes before you print it. Tap a step to jump to it. The rest of the sheet is left for your child to finish.

Read what the video says

0:00 Let's practice addition within 20, step by step.
0:04 Make a ten. For 8 plus 5, take 2 from the 5 to fill up the 8: 8 plus 2 equals 10, then 10 plus 3 equals 13.
0:14 Count the pictures, and write the numbers. 6 plus 7 equals 13.
0:20 Solve each one. 12 plus 6 is 18.
0:24 Use the number line. Start at 14, and hop forward 1. You land on 15.
0:30 Find the missing number. 13 plus what makes 17? 4.
0:34 Fact family. Use 14, 5 and 19 to write four facts. 14 plus 5 is 19.
0:42 Adam has 7 apples. Noor gives Adam 7 more. How many apples does Adam have now? 7 plus 7 is 14.
0:51 Great job! Now print the free worksheet, and finish the rest on your own.

How to do it

Make a ten. For 8 + 5, take 2 from the 5 to fill up the 8: 8 + 2 = 10, then 10 + 3 = 13.

Teaching tip

If one number is 9, think of it as 10 and take 1 away at the end: 9 + 6 is 10 + 6 – 1 = 15.

Try some

12 + 6 = ?18
14 + 5 = ?19
12 + 5 = ?17
8 + 4 = ?12
15 + 3 = ?18
11 + 6 = ?17
10 + 10 = ?20
16 + 2 = ?18

Tap a problem to see the answer.

Word problems

Adam has 7 apples. Noor gives Adam 7 more. How many apples does Adam have now?Show answer

7 + 7 = 14

There are 7 birds on a branch. 5 more come. How many birds are there now?Show answer

7 + 5 = 12

Leo has 8 crayons. Hana gives Leo 5 more. How many crayons does Leo have now?Show answer

8 + 5 = 13

There are 8 fish in the tank. 4 more come. How many fish are there now?Show answer

8 + 4 = 12

What the worksheets look like

Addition within 20 worksheet with a worked example and problems to count — Page 1: the strategy, then count and write

Addition within 20 word problems worksheet — Page 4: word problems

Common questions

How do you teach addition within 20?

Make a ten. For 8 + 5, take 2 from the 5 to fill up the 8: 8 + 2 = 10, then 10 + 3 = 13. If one number is 9, think of it as 10 and take 1 away at the end: 9 + 6 is 10 + 6 – 1 = 15.

What grade is addition within 20?

Usually 1st and 2nd grade. In the Common Core it is part of 1.OA.C.6, 2.OA.B.2.

Is there an answer key?

Yes. Page 5 has every answer from the pack and a short teaching tip. The worksheet maker also adds an answer key to every sheet it makes.