In mathematics, 1 is the multiplicative identity, meaning that any number multiplied by 1 equals the same number. 1 is by convention not considered a prime number. Nov 30, 2025 · Roman numerals are a system of numerical notation based on the ancient Roman system. The symbols are I, V, X, L, C, D, and M, standing respectively for 1, 5, 10, 50, 100, 500, and 1,000 in the Hindu-Arabic numeral system. Dec 9, 2025 · Tenth century “West Arabic” variation of the Nepali form of Hindu-Arabic numerals (compare Devanagari script १ (1, “éka”)), possibly influenced by Roman numeral Ⅰ, both ultimately from using a single stroke to represent the number one. one 1 of 4 adjective ˈwən Synonyms of one 1 : being a single unit or thing one day at a time The glyph used today in the Western world to represent the number 1, a vertical line, often with a serif at the top and sometimes a short horizontal line at the bottom, traces its roots back to the Indians, who wrote 1 as a horizontal line, as is still the case in Chinese script. Explore the curious properties of number 1, an odd number which is uniquely neither prime nor composite. Includes mathematical info, prime factorization, divisors, bases and much more! A fascinating reference for students, coders, engineers, scientists, puzzle-solvers, and anyone who enjoys numbers. 1 Definitions of 1 noun the smallest whole number or a numeral representing this number synonyms: I, ace, one, single, unity 1 is the Hindu-Arabic numeral for the number one (the unit). It is the smallest positive integer, and smallest natural number. 1 is the multiplicative identity, i.e. any number multiplied by 1 equals itself, for example: a ⋅ 1 = a {\displaystyle a \cdot 1=a} and 1 × a = a {\displaystyle 1\times Dec 3, 2025 · Although the number 1 used to be considered a prime number, it requires special treatment in so many definitions and applications involving primes greater than or equal to 2 that it is usually placed into a class of

its own (Wells 1986, p. 31). Number 1 has the same representation in all common number bases: 1. Roman numeral: I. Mathematical properties: square = 1, square root = 1, natural logarithm = 0, decimal logarithm = 0.