Use this page when you want 1st grade addition within 20 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. The current sheet starts with problems like 9 + 9 and 8 + 3, and the answers (18 and 11) are printed on the key so marking takes about a minute.
‘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.
What separates a confident adder from a slow one is rarely the method; it is whether the number bonds underneath are automatic. Watch how long the child hesitates before writing the first digit of 11.
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 + 9 the answer 18 should come from memory, not from counting.
Addition is the first place a child meets the idea of a carried digit, and it is the skill every later algorithm leans on. A sheet like 9 + 9 looks small, but the habit it builds — line up the places, work right to left, record the carry — is the same habit that survives into multi-digit multiplication.
The problems here use sums between 11 and 18, which keeps the arithmetic honest without turning the page into a copying exercise. 9 + 9 and 8 + 3 are typical of the range.
Teachers usually place 1st grade addition within 20 worksheets alongside the addition strand of most US state standards for this grade, which is where the skill sits in the majority of US state frameworks.
| # | Problem | Answer | What to check |
|---|---|---|---|
| 1 | 9 + 9 = | 18 | Watch for: counting on from the wrong number |
| 2 | 8 + 3 = | 11 | Check: treating a longer number as a bigger one |
| 3 | 7 + 7 = | 14 | Look at: guessing on the near-tens |
| 4 | 2 + 6 = | 8 | Ask about: adding right to left, then reading left to right |
| 5 | 5 + 9 = | 14 | Watch for: forgetting the carried digit |
| 6 | 4 + 2 = | 6 | Check: losing the place columns |
A good first problem to do together is 9 + 9, which comes out at 18. Do 9 + 9 once with the child narrating, then hand over the pencil and start the clock on the other 20 problems.
Work 2 + 6 out loud as a demonstration. It gives 8. Children who hear 2 + 6 reasoned through once at the start of a session make noticeably fewer errors in the ten minutes that follow.
Answers appear next to their question numbers, so a wrong item like 8 + 3 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.
To save these 1st grade addition within 20 worksheets instead of printing them, choose 'Save as PDF' in the printer list. You get the worksheet and the answer key as a single PDF, on Letter or A4 depending on your printer settings.
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 + 9 from a neighbour.
One sheet of 1st grade addition within 20 worksheets a day for two weeks will tell you more about where a 1st grader actually stands than any single long assessment.
→ Free 1st Grade Math Worksheets · → Free Addition Worksheets
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