This page makes free printable adding fractions with like denominators worksheets on demand: press the button and you get a new sheet of 20 problems with a matching answer key, ready for US Letter or A4 paper. Right now the generator is set to problems such as 1/9 + 5/9 (answer 2/3) and 1/6 + 2/6 (answer 1/2); 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.
Because each sheet is new, the child meets different denominators every day rather than becoming fluent in one and stuck in the rest.
Doing this well is what makes unlike denominators tractable later. A child who is fuzzy about 1/6 + 2/6 will find common denominators impossible.
This is the right place to establish what a denominator actually is, because the arithmetic in 4/8 + 1/8 is easy enough that the concept gets the attention.
This sheet uses like denominators from 3 to 12, and answers are given in simplest form so simplification is practised alongside the addition itself, as the item 7/12 + 3/12 on this sheet shows.
In US classrooms these adding fractions with like denominators worksheets are commonly aligned with the fractions strand for grade 4, though the exact wording varies from state to state.
| # | Problem | Answer | What to check |
|---|---|---|---|
| 1 | 1/9 + 5/9 = | 2/3 | Watch for: adding the denominators too |
| 2 | 1/6 + 2/6 = | 1/2 | Check: leaving the answer unsimplified |
| 3 | 4/8 + 1/8 = | 5/8 | Look at: subtracting in the wrong order |
| 4 | 6/10 + 3/10 = | 9/10 | Ask about: writing an improper fraction when a mixed number is expected |
| 5 | 7/12 + 3/12 = | 5/6 | Watch for: simplifying halfway |
| 6 | 2/5 + 1/5 = | 3/5 | Check: losing the whole-number part |
Try 4/8 + 1/8 together before letting the child start alone. The answer to 4/8 + 1/8 is 5/8, and talking through how it was reached takes about a minute and saves several minutes of guessing later in the sheet.
Here is one worked through. 1/6 + 2/6 gives 1/2. If your child arrives somewhere other than 1/2 on 1/6 + 2/6, look at the working rather than the answer: nearly every wrong result comes from a skipped step, not an unknown fact.
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.
Keys are produced by the same code that produces the questions, so a mismatch between question and answer is not possible on these sheets.
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.
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