|
78 (number)
78 (seventy-eight) is the natural number following 77 (number), 77 and followed by 79 (number), 79. In mathematics 78 is: *the dimension of the Simple Lie group#Exceptional cases, exceptional Lie group E6 (mathematics), E6 and several related objects. *a sphenic number, having 3 distinct prime factorization, factors. *an abundant number with an aliquot sum of 90. *a semiperfect number, as a multiple of a perfect number. *the 12th triangular number. *a palindromic number in bases 5 (3035), 7 (1417), 12 (6612), 25 (3325), and 38 (2238). *a Harshad number in bases 3, 4, 5, 6, 7, 13 and 14. *an Erdős–Woods number, since it is possible to find sequences of 78 consecutive integers such that each inner member shares a factor with either the first or the last member. 77 and 78 form a Ruth-Aaron pair. In science *The atomic number of platinum. In other fields 78 is also: *In reference to gramophone records, 78 refers those meant to be spun at 78 revolutions per minute. Compare: gram ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural Number
In mathematics, the natural numbers are those numbers used for counting (as in "there are ''six'' coins on the table") and ordering (as in "this is the ''third'' largest city in the country"). Numbers used for counting are called ''Cardinal number, cardinal numbers'', and numbers used for ordering are called ''Ordinal number, ordinal numbers''. Natural numbers are sometimes used as labels, known as ''nominal numbers'', having none of the properties of numbers in a mathematical sense (e.g. sports Number (sports), jersey numbers). Some definitions, including the standard ISO/IEC 80000, ISO 80000-2, begin the natural numbers with , corresponding to the non-negative integers , whereas others start with , corresponding to the positive integers Texts that exclude zero from the natural numbers sometimes refer to the natural numbers together with zero as the whole numbers, while in other writings, that term is used instead for the integers (including negative integers). The natural ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Fool (Tarot Card)
The Fool is one of the 78 cards in a tarot deck. In tarot card reading, it is one of the 22 Major Arcana, sometimes numbered as 0 (the first) or XXII (the last). However, in decks designed for playing traditional tarot card games, it is typically unnumbered, as it is not one of the 21 trump cards and instead serves a unique purpose by itself. Iconography The Fool is titled ''Le Mat'' in the Tarot of Marseilles, and ''Il Matto'' in most Italian language tarot decks. These archaic words mean "the madman" or "the beggar", and may be related to the word for 'checkmate' in relation to the original use of tarot cards for gaming purposes. In the earliest tarot decks, the Fool is usually depicted as a beggar or a vagabond. In the Visconti-Sforza tarot deck, the Fool wears ragged clothes and stockings without shoes, and carries a stick on his back. He has what appear to be feathers in his hair. His unruly beard and feathers may relate to the tradition of the woodwose or wild man. Anot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trump Cards
A trump is a playing card which is elevated above its usual rank in trick-taking games. Typically, an entire suit is nominated as a ''trump suit''; these cards then outrank all cards of plain (non-trump) suits. In other contexts, the terms ''trump card'' or ''to trump'' refers to any sort of action, authority, or policy which automatically prevails over all others. Etymology The English word ''trump'' derives from '' trionfi'', a type of 15th-century Italian playing cards, from the Latin '' triumphus'' "triumph, victory procession", ultimately (via Etruscan) from Greek θρίαμβος, the term for a hymn to Dionysus sung in processions in his honour. ''Trionfi'' was the 15th-century card game for which tarot cards were designed. ''Trionfi'' were a fifth suit in the card game which acted as permanent trumps. Still in the 15th century, the French game ''triomphe'' (Spanish '' triunfo'') used four suits, one of which was randomly selected as trumps. It was this game that becam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tarot
The tarot (, first known as '' trionfi'' and later as ''tarocchi'' or ''tarocks'') is a pack of playing cards, used from at least the mid-15th century in various parts of Europe to play card games such as Tarocchini. From their Italian roots, tarot playing cards spread to most of Europe evolving into a family of games that includes German Grosstarok and more recent games such as French Tarot and Austrian Königrufen which are still played today. In the late 18th century, French occultists began to make elaborate, but unsubstantiated, claims about their history and meaning, leading to the emergence of custom decks for use in divination via tarot card reading and cartomancy. Thus there are two distinct types of tarot pack: those used for playing games and those used for divination. However, some older patterns, such as the Tarot de Marseille, originally intended for playing card games, have also been used for cartomancy. Like the common playing cards, tarot has four suits whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forty Five
45 (forty-five) is the natural number following 44 and followed by 46. In mathematics Forty-five is the smallest odd number that has more divisors than n+1, and that has a larger sum of divisors than n+1. It is the sixth positive integer with a prime factorization of the form p^q, with and being prime. Forty-five is the sum of all single-digit decimal digits: 0+1+2+3+4+5+6+7+8+9=45. It is, equivalently, the ninth triangle number. Forty-five is also the fourth hexagonal number and the second hexadecagonal number, or 16-gonal number. It is also the second smallest triangle number (after 1 and 10) that can be written as the sum of two squares. Since the greatest prime factor of 45^+1=2026 is 1,013, which is much more than 45 twice, 45 is a Størmer number. In decimal, 45 is a Kaprekar number and a Harshad number. Forty-five is a little Schroeder number; the next such number is 197, which is the 45th prime number. Forty-five is conjectured from Ramsey number ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thirty Three
33 (thirty-three) is the natural number following 32 and preceding 34. In mathematics 33 is: * the largest positive integer that cannot be expressed as a sum of different triangular numbers. * the smallest odd repdigit that is not a prime number. * the sum of the first four positive factorials. * the sum of the sum of the divisors of the first 6 positive integers. * the sum of three cubes: 33=8866128975287528^+(-8778405442862239)^+(-2736111468807040)^. * equal to the sum of the squares of the digits of its own square in bases 9, 16 and 31. ** For numbers greater than 1, this is a rare property to have in more than one base. * the smallest integer such that it and the next two integers all have the same number of divisors. * the first member of the first cluster of three semiprimes (33, 34, 35); the next such cluster is 85, 86, 87. * the first double digit centered dodecahedral number. * divisible by the number of prime numbers (11) below 33. * a palindrome in both decimal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Revolutions Per Minute
Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or with the notation min−1) is a unit of rotational speed or rotational frequency for rotating machines. Standards ISO 80000-3:2019 defines a unit of rotation as the dimensionless unit equal to 1, which it refers to as a revolution, but does not define the revolution as a unit. It defines a unit of rotational frequency equal to s−1. The superseded standard ISO 80000-3:2006 did however state with reference to the unit name 'one', symbol '1', that "The special name revolution, symbol r, for this unit is widely used in specifications on rotating machines." The International System of Units (SI) does not recognize rpm as a unit, and defines the unit of frequency, Hz, as equal to s−1. :\begin 1~&\text &&=& 60~&\text \\ \frac~&\text &&=& 1~&\text \end A corresponding but distinct quantity for describing rotation is angular velocity, for which the SI unit is the ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gramophone Record
A phonograph record (also known as a gramophone record, especially in British English), or simply a record, is an analog sound storage medium in the form of a flat disc with an inscribed, modulated spiral groove. The groove usually starts near the periphery and ends near the center of the disc. At first, the discs were commonly made from shellac, with earlier records having a fine abrasive filler mixed in. Starting in the 1940s polyvinyl chloride became common, hence the name vinyl. The phonograph record was the primary medium used for music reproduction throughout the 20th century. It had co-existed with the phonograph cylinder from the late 1880s and had effectively superseded it by around 1912. Records retained the largest market share even when new formats such as the compact cassette were mass-marketed. By the 1980s, digital media, in the form of the compact disc, had gained a larger market share, and the record left the mainstream in 1991. Since the 1990s, records con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Platinum
Platinum is a chemical element with the symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal. Its name originates from Spanish , a diminutive of "silver". Platinum is a member of the platinum group of elements and group 10 of the periodic table of elements. It has six naturally occurring isotopes. It is one of the rarer elements in Earth's crust, with an average abundance of approximately 5 μg/kg. It occurs in some nickel and copper ores along with some native deposits, mostly in South Africa, which accounts for ~80% of the world production. Because of its scarcity in Earth's crust, only a few hundred tonnes are produced annually, and given its important uses, it is highly valuable and is a major precious metal commodity. Platinum is one of the least reactive metals. It has remarkable resistance to corrosion, even at high temperatures, and is therefore considered a noble metal. Consequent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atomic Number
The atomic number or nuclear charge number (symbol ''Z'') of a chemical element is the charge number of an atomic nucleus. For ordinary nuclei, this is equal to the proton number (''n''p) or the number of protons found in the nucleus of every atom of that element. The atomic number can be used to uniquely identify ordinary chemical elements. In an ordinary uncharged atom, the atomic number is also equal to the number of electrons. For an ordinary atom, the sum of the atomic number ''Z'' and the neutron number ''N'' gives the atom's atomic mass number ''A''. Since protons and neutrons have approximately the same mass (and the mass of the electrons is negligible for many purposes) and the mass defect of the nucleon binding is always small compared to the nucleon mass, the atomic mass of any atom, when expressed in unified atomic mass units (making a quantity called the "relative isotopic mass"), is within 1% of the whole number ''A''. Atoms with the same atomic number but dif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erdős–Woods Number
In number theory, a positive integer is said to be an Erdős–Woods number if it has the following property: there exists a positive integer such that in the sequence of consecutive integers, each of the elements has a non-trivial common factor with one of the endpoints. In other words, is an Erdős–Woods number if there exists a positive integer such that for each integer between and , at least one of the greatest common divisors or is greater than . Examples The first Erdős–Woods numbers are : 16, 22, 34, 36, 46, 56, 64, 66, 70, 76, 78, 86, 88, 92, 94, 96, 100, 106, 112, 116 … . History Investigation of such numbers stemmed from the following prior conjecture by Paul Erdős: :There exists a positive integer such that every integer is uniquely determined by the list of prime divisors of . Alan R. Woods investigated this question for his 1981 thesis. Woods conjectured that whenever , the interval always includes a number coprime to both en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
