# Egyptian fraction

An Egyptian fraction is a unit fraction, in other words, a fraction in which the numerator (the number on top) is 1. This type of fraction was the only kind used by the ancient Egyptians and appears extensively in the Rhind papyrus. Other fractions can be obtained by adding Egyptian fractions together; for example, 5/7 = 1/2 + 1/6 + 1/21. In 1201 Fibonacci proved that every rational number can be written as a sum of Egyptian fractions.