Use this page when you want 1st grade subtraction 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 version loaded below opens with items in the shape of 16 − 9 and 10 − 8; the key lists 7 and 2 next to their question numbers.
‘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.
There are two ways to think about a subtraction such as 16 − 9: taking away, or finding the difference. Children who only know the first find 7 slowly whenever the two numbers are close together.
This sheet uses minuends from 11 to 18. That is deliberate: wide enough to force real regrouping, narrow enough that a child can still check the answer by adding back.
Fluency here means the child can say why a column needed regrouping, not just that it did. Ask about the column that produced 7 and you will hear the difference immediately.
Because the sheet regenerates, the child meets the borrowing pattern in a different place each time, which is exactly what stops the method from being memorised as a sequence of pen strokes; 10 − 6 today will not borrow in the same column as tomorrow's sheet.
Teachers usually place 1st grade subtraction within 20 worksheets alongside the subtraction 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 | 16 − 9 = | 7 | Watch for: reading the minus sign as a plus |
| 2 | 10 − 8 = | 2 | Check: checking by re-subtracting |
| 3 | 15 − 8 = | 7 | Look at: forgetting to reduce the column that was borrowed from |
| 4 | 10 − 6 = | 4 | Ask about: subtracting the smaller digit from the larger one |
| 5 | 13 − 4 = | 9 | Watch for: counting back one at a time |
| 6 | 3 − 1 = | 2 | Check: borrowing across a zero |
Work 10 − 6 out loud as a demonstration. It gives 4. Children who hear 10 − 6 reasoned through once at the start of a session make noticeably fewer errors in the ten minutes that follow.
A good first problem to do together is 16 − 9, which comes out at 7. Do 16 − 9 once with the child narrating, then hand over the pencil and start the clock on the other 20 problems.
Keys are produced by the same code that produces the questions, so a mismatch between question and answer is not possible on these sheets.
The answer key is generated with the worksheet, not written by hand, so it always matches the sheet in front of you — 16 − 9 is listed as 7, 10 − 8 as 2, and so on down the page.
If the problems look cramped, drop the count from 20 to a smaller number before printing these 1st grade subtraction within 20 worksheets; the font stays the same size and the spacing opens up.
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 16 − 9 from a neighbour.
Keep the finished 1st grade subtraction within 20 worksheets in date order — the drop in time across ten sheets is the clearest progress report you will get.
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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