3 (THREE; /ˈθriː/ ) is a number , numeral , and glyph . It is the natural number following 2 and preceding 4 .
* 1 Evolution of the glyph
* 1.1 Flat top 3
* 2 In mathematics
* 2.1 In numeral systems * 2.2 List of basic calculations
* 3 In science
* 3.1 In protoscience * 3.2 In pseudoscience
* 4 In philosophy
* 5 In religion
* 5.1 In
* 6 In sports * 7 See also * 8 References * 9 External links
EVOLUTION OF THE GLYPH
Three is the largest number still written with as many lines as the
number represents. (The Ancient Romans usually wrote 4 as IIII, but
this was almost entirely replaced by the subtractive notation IV in
the Middle Ages.) To this day 3 is written as three lines in Roman and
While the shape of the 3 character has an ascender in most modern typefaces , in typefaces with text figures the character usually has a descender , as, for example, in . In some French text-figure typefaces, though, it has an ascender instead of a descender.
FLAT TOP 3
A common variant of the digit 3 has a flat top, similar to the character Ʒ (ezh ). This form is sometimes used to prevent people from fraudulently changing a 3 into an 8. It is usually found on UPC-A barcodes and standard 52-card decks .
* a rough approximation of π (3.1415...) and a very rough
approximation of e (2.71828..) when doing quick estimates.
* the number of non-collinear points needed to determine a plane and
a circle .
* the first odd prime number and the second smallest prime.
* the first
Fermat prime (22n + 1).
* the first
Three is the only prime which is one less than a perfect square . Any other number which is n2 − 1 for some integer n is not prime, since it is (n − 1)(n + 1). This is true for 3 as well (with n = 2), but in this case the smaller factor is 1. If n is greater than 2, both n − 1 and n + 1 are greater than 1 so their product is not prime.
A natural number is divisible by three if the sum of its digits in base 10 is divisible by 3. For example, the number 21 is divisible by three (3 times 7) and the sum of its digits is 2 + 1 = 3. Because of this, the reverse of any number that is divisible by three (or indeed, any permutation of its digits) is also divisible by three. For instance, 1368 and its reverse 8631 are both divisible by three (and so are 1386, 3168, 3186, 3618, etc.). See also Divisibility rule . This works in base 10 and in any positional numeral system whose base divided by three leaves a remainder of one (bases 4, 7, 10, etc.).
Three of the five
There are only three distinct 4×4 panmagic squares .
The trisection of the angle was one of the three famous problems of antiquity.
IN NUMERAL SYSTEMS
There is some evidence to suggest that early man may have used counting systems which consisted of "One, Two, Three" and thereafter "Many" to describe counting limits. Early peoples had a word to describe the quantities of one, two, and three but any quantity beyond was simply denoted as "Many". This is most likely based on the prevalence of this phenomenon among people in such disparate regions as the deep Amazon and Borneo jungles, where western civilization's explorers have historical records of their first encounters with these indigenous people.
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 10000
3 × X 3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48 51 54 57 60 63 66 69 72 75 150 300 3000 30000
DIVISION 1 2 3 4 5 6 7 8 9 10
11 12 13 14 15 16 17 18 19 20
3 ÷ X 3 1 .5 1 0 .75 0.6 0.5 0.428571 0.375 0.3 0.3
0.27 0.25 0.230769 0.2142857 0.2 0.1875 0.17647058823529411 0.16 0.157894736842105263 0.15
X ÷ 3 0.3 0.6 1 1.3 1.6 2 2.3 2.6 3 3.3
3.6 4 4.3 4.6 5 5.3 5.6 6 6.3 6.6
EXPONENTIATION 1 2 3 4 5 6 7 8 9 10
11 12 13 14 15 16 17 18 19 20
3X 3 9 27 81 243 729 2187 6561 19683 59049
177147 531441 1594323 4782969 14348907 43046721 129140163 387420489 1162261467 3486784401
X3 1 8 27 64 125 216 343 512 729 1000
1331 1728 2197 2744 3375 4096 4913 5832 6859 8000
* The Roman numeral III stands for giant star in the Yerkes spectral
classification scheme .
* Three is the atomic number of lithium .
* Three is the
* In European alchemy , the three primes (Latin: tria prima) were
salt ( ), sulfur ( ) and mercury ( ).
* The three doshas (weaknesses) and their antidotes are the basis of
* Three is the symbolic representation for Mu , Augustus Le Plongeon 's and James Churchward 's lost continent.
Main article: Trichotomy (philosophy)
* Philosophers such as
Many world religions contain triple deities or concepts of trinity, including:
* The threefold office of Christ is a Christian doctrine that Christ
performs the functions of prophet , priest , and king .
* The ministry of Jesus lasted approximately three years (27-30 AD).
* During the
Agony in the Garden
Imperial Regalia of Japan
* The Three Treasures (Chinese : 三寶; pinyin : sānbǎo;
Wade–Giles : san-pao), the basic virtues in
* The three virtues of Humata, Hukhta and Huvarshta (Good Thoughts,
Good Words and Good Deeds) are a basic tenet in
IN NORSE MYTHOLOGY
Three is a very significant number in
* Prior to
IN OTHER RELIGIONS
IN ESOTERIC TRADITION
AS A LUCKY OR UNLUCKY NUMBER
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Three (三, formal writing: 叁, pinyin sān,
Counting to three is common in situations where a group of people wish to perform an action in synchrony : Now, on the count of three, everybody pull! Assuming the counter is proceeding at a uniform rate, the first two counts are necessary to establish the rate, and the count of "three" is predicted based on the timing of the "one" and "two" before it. Three is likely used instead of some other number because it requires the minimal amount counts while setting a rate.
In East and
There is another superstition that it is unlucky to take a third light , that is, to be the third person to light a cigarette from the same match or lighter. This superstition is sometimes asserted to have originated among soldiers in the trenches of the First World War when a sniper might see the first light, take aim on the second and fire on the third.
The phrase "Third time\'s the charm" refers to the superstition that after two failures in any endeavor, a third attempt is more likely to succeed. This is also sometimes seen in reverse, as in "third man gets caught".
* In association football a team that wins three trophies in a season is said to have won a treble . * In baseball scorekeeping, "3" denotes the first baseman. * In basketball , the "3 position" is the small forward . * In bowling , three strikes bowled consecutively is known as a "turkey". * In professional wrestling , a pin is when one's shoulders are held the opponent's shoulders against the mat for a count of three. * A "threepeat " is a term for winning three consecutive championships. * A triathlon consists of three events: swimming, bicycling, and running. * In many sports a competitor or team is said to win a Triple Crown if they win three particularly prestigious competitions.