2 ( two) is a number, numeral and numerical digit. It is the natural number following 1 and preceding 3. It is the smallest and the only even prime number.
Because it forms the basis of a duality, it has Religion and Spirituality significance in many Culture.
Mathematics
The number 2 is the second natural number, after 1. Each natural number, including 2, is constructed by succession, that is, by adding 1 to the previous natural number.
2 is the smallest and the only even
prime number, and the first
Ramanujan prime.
It is also the first superior highly composite number,
and the first colossally abundant number.
An integer is determined to be even if it is divisible by two. When written in base 10, all multiples of 2 will end in 0, 2, 4, 6, or 8;
A digon is a polygon with two sides (or edges) and two vertices.
A Set theory that is a field has a minimum of two elements.
Binary number is a number system with a radix of two, it is used extensively in Computer.
List of basic calculations
|
| 2 × x | 2 | 4 | 6 | 8 | 10 | 12 | 14 | 16 | 18 | 20 | 22 | 24 | 26 | 28 | 30 | 32 | 40 | 50 | 100 | 200 | 2000 |
|
|
| 2 ÷ x | 2 | 1 | 0. | 0.5 | 0.4 | 0. | 0. | 0.25 | 0. | 0.2
! | 0. | 0. | 0. | 0. | 0.1 | 0.125 | 0. | 0. | 0. | 0.1 |
| x ÷ 2 | 0.5 | 1 | 1.5 | 2 | 2.5 | 3 | 3.5 | 4 | 4.5 | 5
! | 5.5 | 6 | 6.5 | 7 | 7.5 | 8 | 8.5 | 9 | 9.5 | 10 |
|
|
| 2 | 2 | 4 | 8 | 16 | 32 | 64 | 128 | 256 | 512 | 1024
! | 2048 | 4096 | 8192 | 16384 | 32768 | 65536 | 131072 | 262144 | 524288 | 1048576 |
| x | 1 | 4 | 9 | 16 | 25 | 36 | 49 | 64 | 81 | 100
! | 121 | 144 | 169 | 196 | 225 | 256 | 289 | 324 | 361 | 400 |
As a word
Two is most commonly a determiner used with plural countable nouns, as in
two days or
I'll take these two.
is a
English nouns when it refers to the number two as in
two plus two is four.
The word two is derived from the Old English words twā (feminine), tū (neuter), and twēġen (masculine, which survives today in the form ).
Evolution of the Arabic digit
The digit used in the modern Western world to represent the number 2 traces its roots back to the Indic
Brahmic script, where "2" was written as two horizontal lines. The modern Chinese and Japanese languages (and Korean
Hanja) still use this method. The
Gupta script rotated the two lines 45 degrees, making them diagonal. The top line was sometimes also shortened and had its bottom end curve towards the center of the bottom line. In the
Devanagari script, the top line was written more like a curve connecting to the bottom line. In the Arabic Ghubar writing, the bottom line was completely vertical, and the digit looked like a dotless closing question mark. Restoring the bottom line to its original horizontal position, but keeping the top line as a curve that connects to the bottom line leads to our modern digit.
[Georges Ifrah, The Universal History of Numbers: From Prehistory to the Invention of the Computer transl. David Bellos et al. London: The Harvill Press (1998): 393, Fig. 24.62]
In science
-
The first magic number - number of electrons in the innermost electron shell of an atom.
See also
External links
