1st Grade Math · Addition and Subtraction Within 20
Addition within 10 Worksheets
Free and printable, with a full answer key. Every worksheet is generated fresh, so you can hand a different version to every student.
Sums up to 10, such as 4 + 5 and 7 + 3.
Or start with a ready-made version:
How it works: a quick refresher
For the adult at the table. These are the rules the worksheet practices, followed by one problem worked from start to finish.
| Strategy | How it works |
|---|---|
| Count on | Start at the bigger number and count up the smaller one: 8 + 3 is 9, 10, 11. |
| Make a ten | Split one number to fill a ten: 8 + 5 = 8 + 2 + 3 = 10 + 3 = 13. |
| Use doubles | Doubles are easy to remember, and near doubles follow from them: 6 + 7 = 6 + 6 + 1 = 13. |
| Think addition to subtract | For 13 − 5, ask what number plus 5 makes 13. The answer, 8, is the difference. |
| Count back for small numbers | To take away 1, 2 or 3, count back from the bigger number. |
Worked example
Solve 9 + 6 by making a ten.
- 9 needs 1 more to make 10.
- Split 6 into 1 and 5.
- 9 + 1 = 10.
- 10 + 5 = 15, so 9 + 6 = 15.
Ready-made versions
Three fixed versions you can link to or share. Each is a PDF with its own answer key.
- Addition within 10 Worksheets, version 1Worksheet PDFAnswer key PDF
- Addition within 10 Worksheets, version 2Worksheet PDFAnswer key PDF
- Addition within 10 Worksheets, version 3Worksheet PDFAnswer key PDF
Grade level and standard
Written for 1st grade math (operations) and aligned to CCSS 1.OA.C.6. It also works as review in later grades.
Common questions
- Is there an answer key?
- Yes. Every worksheet has a matching answer key with each answer worked on the same grid or layout as the question. The worksheet ID printed at the bottom of each page pairs a sheet with its key.
- Should my child use fingers or objects?
- Yes, at first. Counting objects builds understanding. Strategies such as making a ten gradually replace counting, and speed comes last.
- How is this different from the 2nd grade facts worksheets?
- This page builds the strategies for adding and subtracting within 20. The 2nd grade facts worksheets are for recalling the same facts quickly from memory.
- How many different versions are there?
- About a million per skill. Each time you press the button the problems are generated fresh, so you can print a different version for every student, a retake, or another night of practice.
- Are the worksheets free?
- Yes. They are free to print and copy for your home or classroom, with no sign-up.