How to use the fraction calculator
- Type a calculation with fractions, for example
2/3 + 5/6,1 1/2 × 3/4or(1/2 + 1/3) ÷ 5/6. Leave a space between the whole number and the fraction in mixed numbers. - The answer appears as a simplified fraction, a mixed number, a decimal and a percentage.
- To turn a decimal into a fraction, use the second box. Repeating decimals are supported with brackets.
How fractions are added, multiplied and simplified
To add or subtract fractions, they need a common denominator: 1/2 + 3/4 = 2/4 + 3/4 = 5/4. To multiply, multiply the tops and the bottoms: 2/3 × 3/5 = 6/15 = 2/5. To divide, multiply by the reciprocal: 1/2 ÷ 3/4 = 1/2 × 4/3 = 2/3. Every result is reduced by dividing the numerator and denominator by their greatest common factor, and improper fractions such as 5/4 are also shown as mixed numbers (1 1/4).
The calculator uses exact whole-number arithmetic with no rounding, however large the numbers get. Decimals you type, such as 0.25, are converted to exact fractions first. Repeating decimals in the answer are marked with brackets, so 1/7 shows as 0.(142857).
Converting a decimal to a fraction: write the digits over a power of ten (0.375 = 375/1000) and simplify (= 3/8). For a repeating decimal like 0.(3), the repeating part becomes nines in the denominator: 3/9 = 1/3.
How do I enter a mixed number?
Type the whole number, a space, then the fraction: 2 3/4. It is read as 2 + 3/4.
Why is 2 1/2 × 2 not 4 1/2?
A mixed number is a single value (2.5), so 2 1/2 × 2 = 5. Multiply the whole value, not only the fraction part.
What is 0.333… as a fraction?
Exactly 1/3. Type 0.(3) in the decimal box to see it.