onetwentieth

Onetwentieth, commonly written as 1/20, is a unit fraction representing one part of a whole divided into twenty equal parts. In decimal notation it equals 0.05, and in percent it is 5%. As a reduced fraction, it is in simplest terms since the greatest common divisor of 1 and 20 is 1.

In mathematics, onetwentieth serves as a standard example of a unit fraction and is often used to illustrate fraction operations. For instance, 1/20 plus 3/20 equals 4/20, which simplifies to 1/5. Because 20 factors as 2^2 × 5, the decimal representation 0.05 terminates rather than repeating. It is also the reciprocal of 20.

In practical contexts, one-twentieth of a dollar is five cents, and one-twentieth of an hour is three minutes. In probability, an event with twenty equally likely outcomes has a 1/20 chance of occurring, corresponding to 5 percent.

The term onetwentieth derives from the English words for one and twentieth and is used in mathematics and education to describe a simple fractional quantity. It appears in curricula and reference materials as a canonical example of a basic proper fraction.