Addition and Subtraction Within 20
Free printable addition and subtraction within 20 worksheets for 1st grade. Single-digit facts, mixed on the page, with an optional answer key.
First grade is where addition and subtraction facts become automatic, so these sheets stay inside the single digits: both numbers run from 0 to 9, which puts every sum at 18 or below and every difference at or above zero. Twenty-five problems fit on a page, enough for real practice without filling a sheet a six-year-old will not finish.
Addition and subtraction are both switched on so a page mixes the two, which is closer to how first graders are actually assessed than a page of one operation. Untick one to drill a single skill, or turn on the answer key so the page can be checked without working through it.
What this worksheet covers
- Add and subtract single-digit numbers, with sums up to 18
- Switch between addition and subtraction from one problem to the next
- Build toward answering every fact from memory
Common Core standards
- 1.OA.C.6 Add and subtract within 20, fluently within 10.
- 2.OA.B.2 Fluently add and subtract within 20; know all sums of two one-digit numbers from memory.
Frequently asked questions
How many problems should a first grader do at once?
Twenty to twenty-five is a normal single sitting. If that is too long, switch Half Page on and each sheet becomes two shorter worksheets you can cut apart.
Can I make the numbers smaller?
Yes. Untick the higher digits in either range - leaving only 0 to 5 in both gives facts within 10.
What does fluent mean for these facts?
Answering correctly without counting, in about three seconds a fact. First grade aims for fluency with facts within 10 and for working out facts within 20. Knowing every one of them from memory is a second grade goal.
Where are subtraction facts like 15 - 8?
Not on this page. Both numbers are single digits, so the subtraction starts from 9 or less while the addition reaches 18. The Fact Family page pairs every addition with the subtractions that undo it, which is how the harder subtraction facts are usually taught.
Can I turn this into a timed test?
Yes. Tick Timed test under Advanced options and the sheet prints a time and score box at the top. Mad Minute Math is the page already set up that way, with sixty facts.