# 1

A 1 is a positive prime natural number preceded by 0 and followed by 2.

**AKA:**One.- …

**Example(s):**- [math]2^0[/math]

**Counter-Example(s):**- 2.

**See:**2-Tuple, Even Number, Unary Numeral System, Unary Numeral System, Empty Product.

## References

### 2020

- (Wikipedia, 2020) ⇒ https://en.wikipedia.org/wiki/1 Retrieved:2020-3-14.
**1**(**one**, also called**unit**, and**unity**) is a number, and a numerical digit used to represent that number in numerals. It represents a single entity, the unit of counting or measurement. For example, a line segment of*unit length*is a line segment of length 1. 1 is the smallest positive integer. It is also sometimes considered the first of the infinite sequence of natural numbers, followed by 2, although by other definitions 1 is the second natural number, following 0.The fundamental mathematical property of 1 is to be a multiplicative identity, meaning that any number multiplied by 1 returns that number. Most if not all properties of 1 can be deduced from this. In advanced mathematics, a multiplicative identity is often denoted 1, even if it is not a number. 1 is by convention not considered a prime number; although universal today, this was a matter of some controversy until the mid-20th century.