How to use
- In Arithmetic, enter two numbers and pick + − × ÷.
- Fractions
3/4, mixed numbers1 1/2(with a space), whole numbers5, decimals0.75and repeating decimals0.(3)all work.
- Fractions
- The result is shown as a mixed number, with the simplest fraction, decimal, percent and the steps (common denominator → combine → simplify → mixed number).
- In Simplify & convert, reduce a single fraction to lowest terms or turn a decimal into a fraction.
Methods
| Operation | Method | Example |
|---|---|---|
| Add / subtract | Rewrite over the least common denominator, then combine numerators | 1/2 + 1/3 = 3/6 + 2/6 = 5/6 |
| Multiply | Multiply numerators and denominators | 2/3 × 3/4 = 6/12 = 1/2 |
| Divide | Multiply by the reciprocal of the divisor | 1/2 ÷ 1/4 = 1/2 × 4/1 = 2 |
| Simplify | Divide top and bottom by the greatest common divisor | 6/8 → (6÷2)/(8÷2) = 3/4 |
| Mixed → improper | Whole × denominator + numerator | 1 1/2 = (1×2+1)/2 = 3/2 |
Decimal to fraction: put the digits over a power of ten and simplify (0.375 = 375/1000 = 3/8). For repeating decimals, wrap the repeating part in parentheses: 0.(3) = 3/9 = 1/3 and 0.1(6) = 15/90 = 1/6.
Example
1 1/2 + 2/3:
- Convert to an improper fraction: 1 1/2 = 3/2
- Common denominator (LCD 6): 3/2 + 2/3 = 9/6 + 4/6
- Combine the numerators: (9 + 4)/6 = 13/6
- As a mixed number: 13/6 = 2 1/6 (2.1666…, written 2.1(6))
Things to watch
- Separate the whole number and the fraction with a space.
11/2is read as eleven halves (5 1/2). - A negative mixed number
-1 1/2means −(1 + 1/2) = −3/2, not −1 + 1/2. - Fractions are computed with exact integer arithmetic, so there is no rounding error. Decimal expansions longer than 1,000 digits are cut off with “…”.
FAQ
Why does 1/3 never end as a decimal?
If the simplified denominator has any prime factor other than 2 and 5 (such as 3 or 7), the decimal repeats forever: 1/3 = 0.(3), 1/7 = 0.(142857).
How do I turn a fraction into a ratio or percentage?
The percent appears under the result. For ratios between several numbers use the ratio calculator, and for percentages the percentage calculator.