1
0 1 2 3 4 5 6 7 8 9 → List of numbers — Integers 0 10 20 30 40 50 60 70 80 90 →
Cardinal	1 one
Ordinal	1st first
Numeral system	unary
Factorization	1
Divisors	1
Greek numeral	α'
Roman numeral	I
Roman numeral (Unicode)	Ⅰ, ⅰ
Arabic	١
Ge'ez	፩
Bengali	১
Chinese numeral	一 , 壹
Devanāgarī	१
Hebrew	א (Alef)
Khmer	១
Thai	๑
prefixes	mono- /haplo- (from Greek) uni- (from Latin)
Binary	1
Octal	1
Duodecimal	1
Hexadecimal	1

1 (one) is a number, numeral, and the name of the glyph representing that number. In mathematics Two has many properties in Mathematics. An Integer is called Even if it is divisible by 2 ---- In mathematics Three is the first odd Prime number, and the second smallest prime In mathematics Four is the smallest Composite number, its proper Divisors being and. This article discusses the number five. For the year 5 AD see 5. In mathematics Six is the second smallest Composite number, its proper Divisors being 1, 2 and 3. In mathematics Seven is the fourth Prime number. It is not only a Mersenne prime (since 23 &minus 1 = 7 but also a In mathematics 8 is a Composite number, its Proper divisors being 1, 2, and 4. In mathematics Nine is a Composite number, its proper Divisors being 1 and 3. This is a list of articles about Numbers ( not about Numerals. The integers (from the Latin integer, literally "untouched" hence "whole" the word entire comes from the same origin but via French "Twenty" redirects here For the village in England, see Twenty Lincolnshire. 30 ( thirty) is the Natural number following 29 and preceding 31. 40 ( forty) is the Natural number following 39 and preceding 41. This article discusses the number fifty. For the year 50 CE see 50. 60 ( sixty) is the Natural number following 59 and preceding 61. 70 ( seventy) is the Natural number following 69 and preceding 71. 80 ( eighty) is the Natural number following 79 and preceding 81. 90 ( ninety) is the Natural number preceded by 89 and followed by 91. This article describes cardinal numbers in mathematics For cardinals in linguistics see Names of numbers in English. In linguistics ordinal numbers are the words representing the rank of a number with respect to some order in particular order or position (i A numeral system (or system of numeration) is a Mathematical notation for representing numbers of a given set by symbols in a consistent manner The unary numeral system is the bijective base - 1 Numeral system. In Mathematics, factorization ( also factorisation in British English) or factoring is the decomposition of an object (for In Mathematics, a divisor of an Integer n, also called a factor of n, is an integer which evenly divides n without ʹ the numeral sign redirects here For the accent ´ see Acute accent. Roman numerals are a Numeral system originating in ancient Rome, adapted from Etruscan numerals. The Hindu-Arabic numeral system is a Positional Decimal Numeral system first documented in the ninth century Ge'ez (gez ግዕዝ) also called Ethiopic, is an Abugida script that was originally developed to write Ge'ez, a Semitic language Chinese numerals are characters for writing Numbers in Chinese. is the reconstructed name of the first letter of the Proto-Canaanite alphabet, continued in descended Semitic alphabets as Phoenician Khmer numerals are the numerals used in the Khmer language of Cambodia. Thai numerals (เลขไทย are a set of numerals traditionally used in Thailand, although the Arabic numerals are more common Numerical prefixes are usually derived from the words for numbers in various languages most commonly Greek and Latin, although this is not always the case Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome. The binary numeral system, or base-2 number system, is a Numeral system that represents numeric values using two symbols usually 0 and 1. The octal Numeral system, or oct for short is the base -8 number system and uses the digits 0 to 7 The duodecimal system (also known as base -12 or dozenal) is a Numeral system using twelve as its base. In Mathematics and Computer science, hexadecimal (also base -, hexa, or hex) is a Numeral system with a A number is an Abstract object, tokens of which are Symbols used in Counting and measuring. A glyph is an element of writing Two or more glyphs representing the same symbol whether interchangeable or context-dependent are called Allographs the abstract unit they It represents a single entity. One is sometimes referred to as unity or unit as an adjective. For example, a line segment of "unit length" is a line segment of length 1. In Geometry, a line segment is a part of a line that is bounded by two distinct end points, and contains every point on the line between its end points

In mathematics, it may represent:

• historically, the first ordinal number, though some modern conventions use 0 (number) as the first ordinal
• the natural number following 0 and preceding 2, the multiplicative identity of the integers
• the corresponding real number 1, the multiplicative identity of the real and complex numbers
• in abstract algebra, it is the multiplicative identity

Contents 1 Mathematics 1.1 List of basic calculations 2 Evolution of the glyph 3 In technology 4 See also 5 References

Mathematics

For any number x:

x·1 = 1·x = x (1 is the multiplicative identity)

x/1 = x (see division)

x¹ = x, 1^x = 1, and for nonzero x, x⁰ = 1 (see exponentiation)

Using ordinary addition, we have 1 + 1 = 2. In Set theory, an ordinal number, or just ordinal, is the Order type of a Well-ordered set. In Mathematics, a natural number (also called counting number) can mean either an element of the set (the positive Integers or an In mathematics Two has many properties in Mathematics. An Integer is called Even if it is divisible by 2 In Mathematics, the term identity has several different important meanings An identity is an equality that remains true regardless of the values of The integers (from the Latin integer, literally "untouched" hence "whole" the word entire comes from the same origin but via French In Mathematics, the real numbers may be described informally in several different ways Complex plane In Mathematics, the complex numbers are an extension of the Real numbers obtained by adjoining an Imaginary unit, denoted Abstract algebra is the subject area of Mathematics that studies Algebraic structures such as groups, rings, fields, modules In Mathematics, especially in elementary Arithmetic, division is an arithmetic operation which is the inverse of Multiplication. Addition is the mathematical process of putting things together In mathematics Two has many properties in Mathematics. An Integer is called Even if it is divisible by 2

One cannot be used as the base of a positional numeral system; sometimes tallying is referred to as "base 1", since only one mark (the tally) is needed, but this is not a positional notation. A numeral system (or system of numeration) is a Mathematical notation for representing numbers of a given set by symbols in a consistent manner Tally marks are an implementation of the Unary numeral system.

The logarithms base 1 is undefined, since 1^x=1 and so has no unique inverse function. In Mathematics, the logarithm of a number to a given base is the power or Exponent to which the base must be raised in order to produce In Mathematics, if &fnof is a function from A to B then an inverse function for &fnof is a function in the opposite direction from B

In the real number system, 1 can be represented in two ways as a recurring decimal: as 1. In Mathematics, the real numbers may be described informally in several different ways A Decimal representation of a Real number is called a repeating decimal (or recurring decimal) if at some point it becomes periodic: there is 000. . . and as 0.999... (q. v. ).

In the Von Neumann representation of natural numbers, 1 is defined as the set {0}. In Mathematical logic, the Peano axioms, also known as the Dedekind-Peano axioms or the Peano postulates, are a set of Axioms for the Natural This set has cardinality 1 and hereditary rank 1. In Mathematics, the cardinality of a set is a measure of the "number of elements of the set" In Set theory and related branches of Mathematics, the von Neumann universe, or von Neumann hierarchy of sets, denoted V, is the class Sets like this with a single element are called singletons. In Mathematics, a singleton is a set with exactly one element

In Principia Mathematica, 1 is defined as the set of all singletons. The Principia Mathematica is a 3-volume work on the Foundations of mathematics, written by Alfred North Whitehead and Bertrand Russell In Mathematics, a singleton is a set with exactly one element

In a multiplicative group or monoid, the identity element is sometimes denoted "1", but "e" (from the German Einheit, unity) is more traditional. In Mathematics, a group is a set of elements together with an operation that combines any two of its elements to form a third element In Abstract algebra, a branch of Mathematics, a monoid is an Algebraic structure with a single Associative Binary operation In Mathematics, an identity element (or neutral element) is a special type of element of a set with respect to a Binary operation on that However, "1" is especially common for the multiplicative identity of a ring. In Mathematics, a ring is an Algebraic structure which generalizes the algebraic properties of the Integers though the rational, real (Note that this multiplicative identity is also often called "unity". )

One is its own factorial, and its own square and cube (and so on, as 1 × 1 × . Definition The factorial function is formally defined by n!=\prod_{k=1}^n k . . × 1 = 1). One is the first figurate number of every kind, such as triangular number, pentagonal number and centered hexagonal number to name just a few. A figurate number is a number that can be represented as a regular and discrete geometric pattern (e A triangular number is the sum of the n Natural numbers from 1 to n. A pentagonal number is a Figurate number that extends the concept of triangular and Square numbers to the Pentagon, but unlike the first A centered hexagonal number, or hex number, is a centered Figurate number that represents a Hexagon with a dot in the center and all other dots

Because of the multiplicative identity, if f(x) is a multiplicative function, then f(1) must equal 1. Outside number theory the term multiplicative function is usually used for Completely multiplicative functions This article discusses number theoretic multiplicative

It is also the first and second numbers in the Fibonacci sequence, and is the first number in many mathematical sequences. In Mathematics, the Fibonacci numbers are a Sequence of numbers named after Leonardo of Pisa, known as Fibonacci As a matter of convention, Sloane's early Handbook of Integer Sequences added an initial 1 to any sequence that didn't already have it, and considered these initial 1's in its lexicographic ordering. Sloane's later Encyclopedia of Integer Sequences and its Web counterpart, the On-Line Encyclopedia of Integer Sequences, ignore initial ones in their lexicographic ordering of sequences, because such initial ones often correspond to trivial cases. The On-Line Encyclopedia of Integer Sequences ( OEIS) also cited simply as Sloane's, is an extensive searchable Database of Integer sequences

One is the empty product. In Mathematics, an empty product, or nullary product, is the result of multiplying no numbers

One is the smallest positive odd integer.

One is a harmonic divisor number. In Mathematics, a harmonic divisor number, or Ore number (named after Øystein Ore who defined it in 1948) is a positive integer whose divisors

One is often the internal representation of the Boolean constant true in computer systems. In Computer science, the Boolean datatype, sometimes called the logical datatype, is a Primitive datatype having one of two values

One is neither a prime number nor a composite number, but a unit, like -1 and, in the Gaussian integers, i and -i. In Mathematics, a prime number (or a prime) is a Natural number which has exactly two distinct natural number Divisors 1 A composite number is a positive Integer which has a positive Divisor other than one or itself In Mathematics, a unit in a ( Unital) ring R is an invertible element of R, i A Gaussian integer is a Complex number whose real and imaginary part are both Integers The Gaussian integers with ordinary addition and multiplication of complex Definition By definition the imaginary unit i is one solution (of two of the Quadratic equation The fundamental theorem of arithmetic guarantees unique factorization over the integers only up to units (e. In Number theory, the fundamental theorem of arithmetic (or unique-prime-factorization theorem) states that every Natural number greater than 1 can be written In Mathematics, factorization ( also factorisation in British English) or factoring is the decomposition of an object (for g. 4 = 2² = (-1)⁴×1²³×2²).

One was formerly considered prime by some mathematicians, using the definition that a prime is divisible only by one and itself. In Mathematics, a prime number (or a prime) is a Natural number which has exactly two distinct natural number Divisors 1 However, this complicates the fundamental theorem of arithmetic, so modern definitions exclude units. In Number theory, the fundamental theorem of arithmetic (or unique-prime-factorization theorem) states that every Natural number greater than 1 can be written The last professional mathematician to publicly label 1 a prime number was Henri Lebesgue in 1899. A mathematician is a person whose primary area of study and research is the field of Mathematics. Henri Léon Lebesgue leɔ̃ ləˈbɛg ( June 28, 1875, Beauvais &ndash July 26, 1941, Paris) was a French

One is one of three possible values of the Möbius function: it takes the value one for square-free integers with an even number of distinct prime factors. For the rational functions defined on the complex numbers see Möbius transformation. In Mathematics, a square-free, or quadratfrei, Integer is one divisible by no perfect square, except 1

One is the only odd number in the range of Euler's totient function φ(x), in the cases x = 1 and x = 2. In Number theory, the totient \varphi(n of a Positive integer n is defined to be the number of positive integers less than or equal to

One is the only 1-perfect number (see multiply perfect number). In Mathematics, a multiply perfect number (also called multiperfect number or pluperfect number) is a generalization of a Perfect number.

By definition, 1 is the magnitude or absolute value of a unit vector and a unit matrix (more usually called an identity matrix). The magnitude of a mathematical object is its size a property by which it can be larger or smaller than other objects of the same kind in technical terms an Ordering In Mathematics, the absolute value (or modulus) of a Real number is its numerical value without regard to its sign. In Mathematics, a unit vector in a Normed vector space is a vector (often a spatial vector) whose length is 1 (the unit length In Linear algebra, the identity matrix or unit matrix of size n is the n -by- n Square matrix with ones on the Main Note that the term unit matrix is usually used to mean something quite different. In Linear algebra, the identity matrix or unit matrix of size n is the n -by- n Square matrix with ones on the Main

One is the most common leading digit in many sets of data, a consequence of Benford's law. Benford's law, also called the first-digit law, states that in lists of numbers from many real-life sources of data the leading digit is distributed in a specific

List of basic calculations

Multiplication	1	2	3	4	5	6	7	8	9	10		11	12	13	14	15	16	17	18	19	20		21	22	23	24	25		50	100	1000
	1	2	3	4	5	6	7	8	9	10		11	12	13	14	15	16	17	18	19	20		21	22	23	24	25		50	100	1000

Division	1	2	3	4	5	6	7	8	9	10		11	12	13	14	15
	1	0. In mathematics Two has many properties in Mathematics. An Integer is called Even if it is divisible by 2 ---- In mathematics Three is the first odd Prime number, and the second smallest prime In mathematics Four is the smallest Composite number, its proper Divisors being and. This article discusses the number five. For the year 5 AD see 5. In mathematics Six is the second smallest Composite number, its proper Divisors being 1, 2 and 3. In mathematics Seven is the fourth Prime number. It is not only a Mersenne prime (since 23 &minus 1 = 7 but also a In mathematics 8 is a Composite number, its Proper divisors being 1, 2, and 4. In mathematics Nine is a Composite number, its proper Divisors being 1 and 3. 17 ( seventeen) is the Natural number following 16 and preceding 18. 18 ( eighteen) is the Natural number following 17 and preceding 19. 19 ( nineteen) is the Natural number following 18 and preceding 20. "Twenty" redirects here For the village in England, see Twenty Lincolnshire. 21 ( twenty-one) is the Natural number following 20 and preceding 22. 22 ( twenty-two) is the Natural number following 21 and preceding 23. This article is about the number 23 For the year see 23. For the movies see 23 (film and The Number 23. 24 ( twenty-four) is the Natural number following 23 and preceding 25. 25 ( twenty-five) is the Natural number following 24 and preceding 26. This article discusses the number fifty. For the year 50 CE see 50. In Mathematics, especially in elementary Arithmetic, division is an arithmetic operation which is the inverse of Multiplication. 5		0. 25	0. 2			0. 125		0. 1
	1	2	3	4	5	6	7	8	9	10		11	12	13	14	15

Exponentiation	1	2	3	4	5	6	7	8	9	10		11	12	13	14	15	16	17	18	19	20
	1	1	1	1	1	1	1	1	1	1		1	1	1	1	1	1	1	1	1	1
	1	2	3	4	5	6	7	8	9	10		11	12	13	14	15	16	17	18	19	20

Evolution of the glyph

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 (in Chinese today this is the way it is written). The Gupta wrote it as a curved line, and the Nagari sometimes added a small circle on the left (rotated a quarter turn to the right, this 9-look-alike became the present day numeral 1 in the Gujarati and Punjabi scripts). The Gupta script (or Gupta Brahmi) was used for writing Sanskrit and is associated with the Gupta Empire of India which was a period of material Gujarati (ગુજરાતી Gujǎrātī ? Punjabi may refer to The Punjabi language of Pakistan and India Punjabi grammar List of Punjabi The Nepali also rotated it to the right, but kept the circle small. Nepali is an Indo-Aryan language spoken in Nepal, Bhutan, and some parts of India and Myanmar (Burma ^[1] This eventually became the top serif in the modern numeral, but the occasional short horizontal line at the bottom probably originates from similarity with the Roman numeral I. In some European countries (e. g. , Germany) the little serif at the top is sometimes extended into a long upstroke, sometimes as long as the vertical line, which can lead to confusion with the glyph for seven in other countries. Germany, officially the Federal Republic of Germany ( ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant is a Country in Central Europe. In mathematics Seven is the fourth Prime number. It is not only a Mersenne prime (since 23 &minus 1 = 7 but also a Where the 1 is written with a long upstroke, the number 7 has a horizontal stroke through the vertical line.

While the shape of the 1 character has an ascender in most modern typefaces, in typefaces with text figures the character usually is of x-height, as, for example, in . Typography, an ascender is the portion of a letter in a Latin-derived alphabet that extends above the Mean line of a font. In Typography, a typeface is a set of one or more Fonts designed with stylistic unity each comprising a coordinated set of Glyphs A typeface usually comprises Text figures (also known as non-lining, lowercase, old-style, ranging or hanging figures or numerals are numerals In Typography, the x-height or corpus size refers to the distance between the baseline and the Mean line in a Typeface.

In technology

• The resin identification code used in recycling to identify polyethylene terephthalate. The symbols in the table below belong to the SPI resin identification coding system, developed by the Society of the Plastics Industry in 1988 Uses PET can be semi-rigid to rigid depending on its thickness and is very lightweight

See also

• 0.999...
• −1

References

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