Use this page when you want adding fractions with unlike denominators 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 4/5 + 2/4 and 5/6 + 3/4, and the answers (13/10 and 19/12) 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.
This is the topic where fraction work either clicks or collapses, and the deciding factor is usually whether equivalent fractions are secure.
The common denominator does not have to be the lowest one. Multiplying the two denominators always works, and with unlike denominators from 2 to 9 the extra simplification at the end is a small price for a method that never fails, which is why a line such as 4/5 + 1/3 turns up.
Checking is possible by estimation: each fraction is roughly a half, a bit more or a bit less, and the answer to 5/6 + 3/4 should be in the neighbourhood the estimate suggests.
The generator produces unlike pairs every time, including pairs where one denominator is a multiple of the other — worth spotting in 2/5 + 7/9, because it halves the work.
These adding fractions with unlike denominators worksheets are commonly aligned with the fractions strand for grade 5, and the skill appears in most curricula somewhere around this point.
| # | Problem | Answer | What to check |
|---|---|---|---|
| 1 | 4/5 + 2/4 = | 13/10 | Watch for: finding a common denominator but forgetting the numerators |
| 2 | 5/6 + 3/4 = | 19/12 | Check: adding numerators and denominators straight across |
| 3 | 2/5 + 7/9 = | 53/45 | Look at: using the product when a much smaller common denominator exists |
| 4 | 1/5 + 1/6 = | 11/30 | Ask about: stopping before simplifying |
| 5 | 4/5 + 1/3 = | 17/15 | Watch for: subtracting the larger numerator from the smaller after conversion |
| 6 | 5/6 + 6/9 = | 3/2 | Check: multiplying only one fraction up |
The item 5/6 + 3/4 is worth doing slowly. The answer to 5/6 + 3/4 is 19/12, 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.
Work 1/5 + 1/6 out loud as a demonstration. It gives 11/30. Children who hear 1/5 + 1/6 reasoned through once at the start of a session make noticeably fewer errors in the ten minutes that follow.
Keys are produced by the same code that produces the questions, so a mismatch between question and answer is not possible on these sheets.
Because the numbers are random, there is no shared answer list to look up: the key printed behind your sheet is the only one that fits it, and it shows 13/10 for 4/5 + 2/4.
If the problems look cramped, drop the count from 20 to a smaller number before printing these adding fractions with unlike denominators worksheets; the font stays the same size and the spacing opens up.
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.
Print a sheet of adding fractions with unlike denominators worksheets, run it for 10 minutes, mark it together, and come back tomorrow for a different set of numbers on the same skill.
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