The Roman numeral representation for the number 1 is I.
1 is by convention neither a prime number nor a composite number.
One of the two factors of a prime number is 1.
1 is the smallest possible difference between two distinct natural numbers.
Two intersecting lines in 2D can meet at only 1 point.
1 is the multiplicative identity element for any real (or complex number). If we multiply any number by 1, we get that number again.
The first power of any number is that number. That is, a1 = a for every number a.
The number 1 raised to any power is equal to 1. That is, 1n = 1 for every integer n.
If the product of two natural numbers is 1, then they must both be 1.
The number 1 is represented by both the repeating decimals 1.000… and 0.999….
1 is the factorial value for both 0 and 1: 0! = 1 and 1! = 1. The number 1 is triangular, square, tetrahedral, pyramidal, and octahedral.
If the number of performers in an artistic presentation is 1, then it is called a solo act.
A set with 1 element is called a singleton.
Numbers like 1, 11, 111, … made up entirely of the digit 1, are repunits.
The number 1 is one of two numbers whose Roman numeral spells an English word. What is the other?
In a deck of cards, the ace stands for the number 1.
1 is the probability of a sure event.
1 is the first and second number in the Fibonacci sequence.
1 is the magnitude, absolute value, or norm of a unit complex number, unit vector, and a unit matrix.
In Boolean algebra, 1 represents the value for on. At any given point on the circle, only 1 tangent and 1 normal can be drawn passing through that point.
