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Fraction Calculator

Add, subtract, multiply, and divide fractions with step-by-step solutions and simplified results.

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Fraction result

Result (lowest terms)5/6
Decimal0.833333333333

Step-by-step:

1/2 + 1/3

= (1×3 + 1×2) / (2×3)

= 5/6

How to use the Fraction calculator

Enter fractions like "1/2", negative fractions like "-3/4", mixed numbers like "2 1/3", whole numbers, or decimals such as "0.25". Choose the operation and the result is shown in lowest terms, as a mixed number, and as a decimal — with step-by-step working.

Formula

Addition: a/b + c/d = (a×d + c×b) / (b×d)

Subtraction: a/b − c/d = (a×d − c×b) / (b×d)

Multiplication: a/b × c/d = (a×c) / (b×d)

Division: a/b ÷ c/d = (a×d) / (b×c), where c ≠ 0

The result is reduced by dividing the numerator and denominator by their greatest common divisor (GCD).

Frequently asked questions

How do I simplify a fraction?

Divide both numerator and denominator by their Greatest Common Divisor (GCD). This calculator simplifies results automatically.

How do I enter a mixed number?

Type the whole number, a space, then the fraction — for example 2 1/3. For a negative mixed number type -2 1/3, which means −(2 + 1/3).

Why can a denominator not be zero?

Division by zero is undefined, so a fraction such as 3/0 has no value. The calculator will flag it as an error.

Fraction guide

How to Add and Subtract Fractions

To add or subtract fractions, you need a common denominator. Find the Least Common Multiple (LCM) of both denominators, convert each fraction, then add or subtract the numerators. For example: 1/3 + 1/4 → 4/12 + 3/12 = 7/12. This calculator performs these steps automatically and simplifies the result.

History & interesting facts

Did you know?

The fraction 1/7 produces the repeating decimal 0.142857142857... and if you multiply 142,857 by 2, 3, 4, 5, or 6, you get the same digits in a different cyclic order.

Origin & history

Fractions have been used since ancient Egypt around 1800 BCE. The Egyptians primarily used unit fractions (1/n) and had special symbols for common fractions. The modern fraction notation with a horizontal bar (vinculum) was introduced by Arab mathematicians and popularized in Europe by Fibonacci in his 1202 book Liber Abaci.

Fascinating facts

  1. 1

    Every rational number can be expressed as a fraction of two integers. Irrational numbers like π and √2 cannot be expressed as fractions.

  2. 2

    The ancient Egyptians could only use unit fractions (like 1/2, 1/3, 1/7) and had to express other fractions as sums of unit fractions.

  3. 3

    The fraction bar also serves as a division symbol — 3/4 literally means "3 divided by 4."

  4. 4

    Finding the Greatest Common Divisor (GCD) to simplify fractions uses an algorithm first described by Euclid around 300 BCE.

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