Adding Fractions
Free printable adding fractions worksheets. Like and unlike denominators mixed on one page, with answers in lowest terms.
Twelve addition problems to a sheet, mixing fractions that share a denominator with fractions that do not. That mix is deliberate: a page where every problem needs a common denominator teaches the procedure, but it does not teach a student to check whether they need it.
Set Denominators to Like Denominators for a first sheet where the bottom numbers already match, or to Unlike Denominators once finding a common denominator is the thing being practised. There is a dedicated page for the unlike case.
What this worksheet covers
- Add fractions with like denominators straight across
- Find a common denominator when the denominators differ
- Simplify the sum and write it as a mixed number when it is more than one
Common Core standards
- 4.NF.B.3 Add and subtract fractions and mixed numbers with like denominators.
- 5.NF.A.1 Add and subtract fractions with unlike denominators by finding equivalent fractions.
Frequently asked questions
How do you add fractions with different denominators?
Rewrite both fractions over a common denominator - any common multiple of the two will do, and the product of the denominators always works - then add the numerators and reduce.
Why do fractions need a common denominator before adding?
Because you can only add pieces of the same size. A quarter and a third are different-sized pieces, so 1/4 + 1/3 is not 2/7. Rewritten as twelfths it is 3/12 + 4/12, which is 7/12.
Do the answers ever come out greater than one?
Yes. Both operands are proper fractions but their sum often is not, and those answers are written as mixed numbers.
Can I get only like denominators?
Yes - set Denominators to Like Denominators and every problem on the sheet will share a bottom number.