Adding Fractions with Unlike Denominators
Different denominators on every problem, so the student finds a common denominator before adding. At the easy setting one denominator is always a multiple of the other (1/2 + 3/8), which needs only one conversion; medium and hard use any pair up to tenths or twelfths, where the least common denominator has to be found. Sums past 1 are written as mixed numbers on the key.
Halves to tenths.
Ready-made PDFs
One-click downloads, answer key included, a different puzzle in each.
FAQ
What makes the easy setting easier?
One denominator divides the other, so only one fraction changes: 1/2 + 3/8 becomes 4/8 + 3/8. Medium and hard use pairs like 2/3 + 3/4 where both fractions convert.
How are the answers written on the key?
In lowest terms, and as a mixed number when the result is more than 1 (7/4 shows as 1 3/4). If a student writes an unsimplified but correct fraction, that is a teaching moment rather than a wrong answer; the key shows the form most rubrics expect.
Can students work these on a tablet?
Yes. Practice online puts a pen tool over the same sheet, so the fraction can be written with a stylus or finger and wiped for another try.
How do I print this adding fractions worksheet?
Click Download PDF and print at 100% scale. The page is already sized for US Letter with printer-safe margins, so no fit-to-page fiddling is needed.
Does the key use the least common denominator?
The key shows the final answer in lowest terms, whichever common denominator the student used. Multiplying the denominators works on every problem here; it just means a bigger reduction at the end.
What does the Denominators control change?
The largest denominator the generator may use: 6, 10 or 12. Smaller denominators keep the numbers friendly for a first pass; 12 brings in sevenths, ninths and elevenths, which force the general method instead of pattern-spotting.
Can I get different versions for each student?
Turn on the 5 versions switch before downloading. You get five different sheets in one PDF, each with its own answer key, so neighbouring desks cannot copy.