Every sheet of addition within 20 worksheets on this page is built the moment you open it, so the 20 problems below are not the same ones the last visitor printed, and the answer key is generated with them. A typical problem from the sheet in front of you is 9 + 6, which works out to 15; another is 7 + 5, giving 12.
‘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.
The problems here use sums between 11 and 18, which keeps the arithmetic honest without turning the page into a copying exercise. 9 + 6 and 7 + 5 are typical of the range.
Fluency in addition is usually described in two parts: knowing the single-digit facts by recall, and applying a written method to bigger numbers. This sheet exercises whichever of the two the number range implies — for 9 + 6 the answer 15 should come from memory, not from counting.
Written addition is worth practising in columns — which is what these addition within 20 worksheets ask for — even when a child working at this level can do it mentally, because the column layout is what makes four-digit work manageable later. A problem such as 6 + 5 is small enough to do mentally and worth writing out anyway.
Because the addends are regenerated every time, a child cannot learn the sheet instead of the skill. Yesterday's page may have asked for 9 + 4; today's asks something else in the same shape.
In US classrooms these addition within 20 worksheets are commonly aligned with the addition strand of most US state standards for this grade, though the exact wording varies from state to state.
| # | Problem | Answer | What to check |
|---|---|---|---|
| 1 | 9 + 6 = | 15 | Watch for: counting on from the wrong number |
| 2 | 7 + 5 = | 12 | Check: forgetting the carried digit |
| 3 | 9 + 4 = | 13 | Look at: losing the place columns |
| 4 | 6 + 5 = | 11 | Ask about: guessing on the near-tens |
| 5 | 6 + 6 = | 12 | Watch for: adding right to left, then reading left to right |
| 6 | 5 + 6 = | 11 | Check: treating a longer number as a bigger one |
Here is one worked through. 7 + 5 gives 12. If your child arrives somewhere other than 12 on 7 + 5, look at the working rather than the answer: nearly every wrong result comes from a skipped step, not an unknown fact.
The item 7 + 5 is worth doing slowly. The answer to 7 + 5 is 12, 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.
Answers appear next to their question numbers, so a wrong item like 7 + 5 can be found in the key in a second and re-worked while it is still fresh.
The key prints on its own page by default. Uncheck the answer-key box before printing if you would rather keep it back and mark the sheet yourself.
Printing works the same on US Letter and A4, because the layout uses relative widths rather than fixed inches. Set margins to default and scaling to 100%, and all 20 problems fit.
For a class set, print one sheet, press the new-worksheet button and print again. Each child gets different numbers on the same skill, so nobody can copy the answer to 9 + 6 from a neighbour.
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