2 (number)

2016-11-29T20:08:19Z

184.105.46.131:

{{otherusesof|2|2 (disambiguation)}}
{{redirect|II}}
[[File:En-us-Two.ogg|thumb|right|Pronunciation of the number 2]]

{{Infobox number
| number = 2
| ordinal = 2nd (second / [[wikt:twoth|twoth]])
| numeral = [[binary numeral system|binary]]
| factorization = [[prime number|prime]]
| gaussian integer factorization = <math>(1 + i)(1 - i)</math>
| prime = 1st
| divisor = 1, 2
| roman unicode = Ⅱ, ⅱ
| greek prefix = [[Wiktionary:di-|di-]]
| latin prefix = [[Wiktionary:duo-|duo-]] [[Wiktionary:bi-|bi-]]
| old english prefix = [[Wiktionary:twi-|twi-]]
| lang1 = [[Greek numeral]]
| lang1 symbol = β'
| lang2 = [[Eastern Arabic numerals|Arabic]]
| lang2 symbol = {{resize|150%|٢}}
| lang3 = [[Urdu]]
| lang3 symbol = {{Urdu|2|11|top}}
| lang4 = [[Ge'ez alphabet|Ge'ez]]
| lang4 symbol = ፪
| lang5 = [[Bengali numerals|Bengali]]
| lang5 symbol = {{resize|150%|২}}
| lang6 = [[Chinese numeral]]
| lang6 symbol = 二，弍，贰，貳
| lang7 = [[Devanāgarī]]
| lang7 symbol = {{resize|150%|२}}
| lang8 = [[Indian numerals#Telugu numerals and their names|Telugu]]
| lang8 symbol = {{resize|150%|౨}}
| lang9 = [[Tamil numerals|Tamil]]
| lang9 symbol = {{resize|150%|௨}}
| lang10 = [[Hebrew numerals|Hebrew]]
| lang10 symbol = {{resize|150%|ב}} (Bet)
| lang11 = [[Khmer numerals|Khmer]]
| lang11 symbol = ២
| lang12 = [[Korean numerals|Korean]]
| lang12 symbol = 이，둘
| lang13 = [[Thai numerals|Thai]]
| lang13 symbol = ๒
}}

'''2''' ('''Two'''; {{IPAc-en|audio=En-us-two.ogg|ˈ|t|uː}}) is a [[number]], [[numeral]], and [[glyph]]. It is the number after 1 and the number before 3. In [[Roman numerals]], it is '''II'''.

== In mathematics ==
Two has many meanings in [[math]]. For example: <math> 1 + 1 = 2</math>.<ref>Wells, D. ''The Penguin Dictionary of Curious and Interesting Numbers'' London: Penguin Group. (1987): 41–44</ref> An [[integer]] is ''[[even]]'' if half of it equals an integer. If the last digit of a number is even, then the number is even. This means that if you multiply 2 times anything, it will end in 0, 2, 4, 6, or 8.

Two is the smallest, first, and only even [[prime number]]. The next prime number is [[3 (number)|three]]. Two and three are the only prime numbers next to each other. The even numbers above two are not prime because they are divisible by 2.

[[Fraction (mathematics)|Fractions]] with 2 in the bottom do not yield infinite.

Two is the framework of the [[binary]] system used in computers. The binary way is the simplest [[numeral system|system of numbers]] in which natural numbers (0-9) can be written.

Two also has the unique property that 2+2 = 2·2 = 2<sup>2</sup> and 2! + 2 = 2<sup>2</sup>.

[[Power of two|Powers of two]] are important to [[computer science]].

The [[square root]] of two was the first known [[irrational number]].

== References ==
{{commons|2}}
{{reflist}}

[[Category:Integers]]
[[Category:Prime numbers]]

TCS Wiki - User contributions [en]

2 (number)