Adding Fractions Calculator
Add two or three fractions and see the sum reduced to lowest terms, as a mixed number and decimal, with the common-denominator steps shown.
Sum in lowest terms
5/6
Before reducing the sum is 5/6.
As a mixed number
5/6
As a decimal
0.833333333333
Step by step
- Common denominator = 2 × 3 = 6
- Rewrite each fraction: 3/6 , 2/6
- Add the numerators: 3 + 2 = 5, over 6
- Reduce 5/6 → 5/6
How it works
To add fractions you first need them sitting over the same denominator. This tool finds a common denominator by multiplying the bottoms together, rewrites each fraction to match, then adds the top numbers. If you're only adding two fractions like 1/2 and 1/3, it uses 6 as the shared bottom and turns them into 3/6 and 2/6.
Once the numerators are added, the raw total is reduced by dividing the top and bottom by their greatest common factor. So 5/6 stays 5/6, but a sum that came out as 6/8 would be shown as 3/4. You also get the answer as a mixed number and as a decimal, which is handy when the total climbs above one.
There's an optional third fraction if you're adding three at once — leave it blank to stick with two. Negative numerators are fine; put the minus sign on the top number. Every step, from the common denominator to the final reduction, is written out so you can follow the arithmetic or check homework.
Frequently asked questions
Do the fractions have to have the same denominator?
No. That's the whole point of this tool — it finds a common denominator for you, rewrites each fraction, then adds. You can enter any two (or three) fractions with different bottoms.
Why is my answer shown three different ways?
The reduced fraction is the exact answer in lowest terms. The mixed number is easier to picture when the sum is bigger than one (7/4 becomes 1 3/4), and the decimal is useful if you're plugging the value into something else.
Can I add a negative fraction?
Yes. Put the minus sign on the numerator, for example -1 over 4. The tool tracks the sign through the addition and reports the reduced result with the correct sign.