How the calculator works
Every input is turned into an exact fraction using whole-number (BigInt) arithmetic, so there are no rounding errors even for large numbers. Mixed numbers like 1 1/2 become improper fractions (3/2) first. The result is reduced using the greatest common divisor and then shown three ways: a fraction in lowest terms, a mixed number and a decimal.
Steps you can follow
The step list shows the common denominator for adding and subtracting, or the flip-and-multiply step for division. It is handy for checking homework. For percentages use the percentage calculator, for equations the quadratic equation solver, and for very large or small numbers the scientific notation converter.
Frequently asked questions
How do I add fractions with different denominators?
Find a common denominator, usually the least common multiple, rewrite both fractions with it, add the numerators and simplify. For 1/2 + 1/3 the common denominator is 6, so it becomes 3/6 + 2/6 = 5/6.
How do I multiply and divide fractions?
To multiply, multiply the numerators and multiply the denominators. To divide, flip the second fraction (use its reciprocal) and multiply. For example 1/2 ÷ 1/4 = 1/2 × 4/1 = 2.
How do I write a mixed number?
Type the whole part, a space, then the fraction, for example 2 1/3. You can also type a plain fraction like 7/3, a whole number like 5, or a decimal like 0.75. A minus sign in front makes the whole number negative.
What does simplifying a fraction mean?
Divide the top and bottom by their greatest common divisor until nothing more divides both. 6/8 becomes 3/4 because 2 goes into both.
Can a denominator be zero?
No. A fraction with a zero denominator is not allowed, and dividing by a fraction whose value is zero is not allowed either. The calculator tells you when this happens.