Fraction calculator
All four operations, step by step
- Mixed number
- —
- Decimal
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Worked out in your browser. No sign-up.
Type the numerators and denominators of two fractions and pick an operation. The calculator gives the simplified answer, the mixed number and the decimal, and shows the working underneath: common denominator, equivalent fractions and simplifying. For example 3/4 + 5/6 = 9/12 + 10/12 = 19/12, or 1 7/12. The steps can go straight into homework.
How it works
You can only add or subtract fractions once they share a denominator. So you find the lowest common multiple (LCM) of the denominators and scale each fraction up to it. Then add or subtract the numerators and keep the denominator.
To multiply, multiply top by top and bottom by bottom. To divide, turn the second fraction upside down (2/5 becomes 5/2) and multiply.
Finally simplify: divide top and bottom by their highest common factor. When the numerator is bigger than the denominator, the answer can also be written as a mixed number: 19/12 = 1 7/12.
Worked example
Adding: 2/3 + 1/4. The lowest common multiple of 3 and 4 is 12. So 2/3 = 8/12 and 1/4 = 3/12, which add up to 11/12. That can't be simplified.
Dividing: 3/4 ÷ 9/8. Flip the second fraction and multiply: 3/4 × 8/9 = 24/36. The highest common factor of 24 and 36 is 12, so the answer is 2/3. The calculator shows division as “:”, as Serbian schools write it.
In the kitchen: a recipe needs 3/4 of a cup of flour and you're making half. 3/4 × 1/2 = 3/8 of a cup.
Questions people ask
How do I simplify a fraction?
Divide the numerator and denominator by the same number, ideally their highest common factor. For 18/24 that's 6, giving 3/4.
How do I turn a fraction into a decimal?
Divide the numerator by the denominator: 3/8 = 3 ÷ 8 = 0.375. Some fractions give a recurring decimal, such as 1/3 = 0.333…
How do I enter a mixed number like 2 1/3?
Change it to an improper fraction first: multiply the whole number by the denominator and add the numerator. 2 1/3 = (2 × 3 + 1)/3 = 7/3.
Can I use negative fractions?
Yes. Put a minus sign in front of the numerator: −3 on top and 4 underneath gives −3/4.
What do NZS and NZD mean in Serbian maths homework?
NZS is the lowest common multiple (LCM) and NZD the highest common factor (HCF). Serbian schools also write division as a colon, 3 : 4.
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Updated: 13 November 2026