Use this page when you want doubles worksheets in the next thirty seconds: choose how many problems you want, press print, and the answer key comes out on its own page behind the worksheet. Right now the generator is set to problems such as 2 + 2 (answer 4) and 9 + 9 (answer 18); press the button again and the numbers change while the skill stays the same.
‘New set of problems’ opens the generator in its own tab. There you can change the problem count and turn the answer key on or off. ‘Print or save as PDF’ opens the print dialog — choose Save as PDF in the printer list to keep the file. The sheet fits US Letter and A4, and the answer key prints on its own page.
Doubling is also halving in reverse, so this sheet quietly builds the division facts that come a year or two later.
This sheet uses doubles from 1 + 1 up to 12 + 12, which covers the doubles children need before moving into two-digit work.
The strategy that makes them valuable is 'doubles plus one': knowing a double lets a child reach the neighbouring fact without counting.
Speed is the measurement here rather than accuracy. Almost every child reaches 4 eventually; the point is that they should not have to work it out.
Work of this kind is commonly aligned with the addition fluency expectations for grade 1; schools outside the US meet the same skill at roughly the same age, which is why these doubles worksheets travel well.
| # | Problem | Answer | What to check |
|---|---|---|---|
| 1 | 2 + 2 = | 4 | Watch for: doubling only one digit in a two-digit number |
| 2 | 9 + 9 = | 18 | Check: counting on rather than recalling |
| 3 | 1 + 1 = | 2 | Look at: losing the larger doubles |
| 4 | 12 + 12 = | 24 | Ask about: treating each double as unrelated |
| 5 | 11 + 11 = | 22 | Watch for: confusing doubling with adding one |
| 6 | 5 + 5 = | 10 | Check: practising in order every time |
A good first problem to do together is 2 + 2, which comes out at 4. Do 2 + 2 once with the child narrating, then hand over the pencil and start the clock on the other 20 problems.
The item 9 + 9 is worth doing slowly. The answer to 9 + 9 is 18, and the route to it is the route every other problem on this sheet takes — which is why the sheet has 20 of them rather than one.
Keys are produced by the same code that produces the questions, so a mismatch between question and answer is not possible on these sheets.
Every generated sheet carries its own key on a separate printed page, which lets a child self-mark without seeing the answers while they work.
Portrait orientation is what the sheet is designed for. Landscape works but wastes about a third of the paper, so leave the orientation alone unless you have a reason.
The sheet is laid out to fit one page on both US Letter and A4. Leave the browser scaling at 100% and turn headers and footers off, and the 20 problems land inside the margins on either paper size.
When these become easy, move along the related links below rather than adding more problems to the same sheet.
Free printable math worksheets from a working math academy director in Korea. Problems come from our own code, not from a published workbook. Every sheet prints on US Letter or A4 with its answer key. All worksheets · Worksheet generator · Korean site
Last updated: 2026-09-13