Fraction Calculator
Add, subtract, multiply or divide two fractions or mixed numbers. Exact answer in lowest terms, with mixed number, decimal and the steps. How it works
Use the Fraction Calculator
About the Fraction Calculator
1/2 + 1/3 = 5/6, or 0.8333 as a decimal. Enter each fraction as a whole-number numerator and denominator, pick +, -, × or ÷, and the answer is worked out exactly and reduced to lowest terms. A mixed number such as 1 1/2 goes in through the optional Whole box in front of the fraction: 1 in Whole, 1 on top, 2 below. The result also shows a mixed number when it is 1 or more in size, and a decimal rounded to four places.
Fraction results
| Calculation | Result | Mixed number | Decimal |
|---|---|---|---|
| 1/2 + 1/3 | 5/6 | None | 0.8333 |
| 5/6 - 1/4 | 7/12 | None | 0.5833 |
| 3/4 × 2/3 | 1/2 | None | 0.5 |
| 7/8 ÷ 1/4 | 7/2 | 3 1/2 | 3.5 |
| 1/2 - 3/4 | -1/4 | None | -0.25 |
| -7/4 + 0/1 | -7/4 | -1 3/4 | -1.75 |
| 3/4 + 3/4 | 3/2 | 1 1/2 | 1.5 |
| 4/6 + 0/1 | 2/3 | None | 0.6667 |
As the tool shows them. The whole part of a mixed number truncates toward zero, so -7/4 is -1 3/4.
How to use this tool
- Enter the first numerator and denominator, plus a whole number in the Whole box if it is a mixed number, and choose +, -, × or ÷.
- Enter the second numerator and denominator. The result appears once all four boxes are filled and follows each edit.
- Read the reduced fraction, the mixed number (if any), the decimal and the numbered steps under them. A message under a box names a value that cannot be used, such as a zero denominator.
Frequently asked questions
- How do I add fractions with different denominators?
- Cross-multiply, add, then reduce: a/b + c/d = (a × d + c × b) ÷ (b × d). For 1/2 + 1/3 that is (1 × 3 + 1 × 2) ÷ 6 = 5/6. The numbered steps under the result take the textbook route: the least common denominator of 2 and 3 is 6, so 3/6 + 2/6 = 5/6, already in lowest terms.
- How do I subtract fractions?
- Use the same cross-multiplication with a minus: 5/6 - 1/4 = (5 × 4 - 1 × 6) ÷ 24 = 14/24 = 7/12, or 0.5833. A negative answer keeps its sign on the numerator: 1/2 - 3/4 = -1/4.
- How do I multiply and divide fractions?
- To multiply, multiply across: 3/4 × 2/3 = 6/12 = 1/2. To divide, multiply by the second fraction flipped over: 7/8 ÷ 1/4 = 28/8 = 7/2, shown as 3 1/2 and 3.5. The steps under the result show the same: 1/2 ÷ 3/4 = 1/2 × 4/3 = 4/6, which reduces by 2 to 2/3.
- How do I enter a mixed number like 1 1/2?
- Type 1 in the Whole box, 1 on top and 2 below. 1 1/2 + 2 1/4 gives 15/4, shown as 3 3/4 and 3.75, and the first step writes 1 1/2 as 3/2 (1 × 2 + 1 = 3, over 2). For a negative mixed number put the minus on the whole number: −1 1/2 + 1/4 gives -5/4, or -1 1/4. Improper fractions still work: 1 1/2 + 2 3/4 typed as 3/2 + 11/4 gives 17/4, shown as 4 1/4 and 4.25.
- How do I simplify a fraction?
- Every answer is divided by the greatest common divisor, so it is always in lowest terms. To reduce one fraction on its own, add 0/1 to it: 18/24 + 0/1 gives 3/4.
- Are the results exact for large numbers?
- Yes. Numerators and denominators up to 100 digits are handled as exact whole numbers, so 1/1000000007 + 1/1000000009 gives 2000000016/1000000016000000063, not a rounded value. Inputs such as 1e3 or 2.5 are refused with a message; write 2.5 as 5/2.
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