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87 (number)
87 (eighty-seven) is the natural number following 86 (number), 86 and preceding 88 (number), 88. In mathematics 87 is: * the sum of the squares of the first four primes (87 = 22 + 32 + 52 + 72). * the sum of the sums of the divisors of the first 10 positive integers. * the thirtieth semiprime, and the twenty-sixth distinct semiprime and the eighth of the form (3.q). * together with 85 (number) , 85 and 86 (number), 86, forms the last semiprime in the 2nd cluster of three consecutive semiprimes; the first comprising 33 (number), 33, 34 (number), 34, 35 (number), 35. * with an aliquot sum of 33 (number), 33; itself a semiprime, within an aliquot sequence of five composite numbers (87,33 (number), 33,15 (number), 15,9 (number), 9,4 (number), 4,3 (number), 3,1 (number), 1,0) to the Prime in the 3 (number), 3-aliquot tree. * 5! - 4! - 3! - 2! - 1! = 87 * the last two decimal digits of Graham's number. In sports * Cricket in Australia holds 87 as a superstitiously unlucky score and is r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural Number
In mathematics, the natural numbers are the numbers 0, 1, 2, 3, and so on, possibly excluding 0. Some start counting with 0, defining the natural numbers as the non-negative integers , while others start with 1, defining them as the positive integers Some authors acknowledge both definitions whenever convenient. Sometimes, the whole numbers are the natural numbers as well as zero. In other cases, the ''whole numbers'' refer to all of the integers, including negative integers. The counting numbers are another term for the natural numbers, particularly in primary education, and are ambiguous as well although typically start at 1. The natural numbers are used for counting things, like "there are ''six'' coins on the table", in which case they are called ''cardinal numbers''. They are also used to put things in order, like "this is the ''third'' largest city in the country", which are called ''ordinal numbers''. Natural numbers are also used as labels, like Number (sports), jersey ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
3 (number)
3 (three) is a number, numeral and digit. It is the natural number following 2 and preceding 4, and is the smallest odd prime number and the only prime preceding a square number. It has religious and cultural significance in many societies. Evolution of the Arabic digit The use of three lines to denote the number 3 occurred in many writing systems, including some (like Roman and Chinese numerals) that are still in use. That was also the original representation of 3 in the Brahmic (Indian) numerical notation, its earliest forms aligned vertically. However, during the Gupta Empire the sign was modified by the addition of a curve on each line. The Nāgarī script rotated the lines clockwise, so they appeared horizontally, and ended each line with a short downward stroke on the right. In cursive script, the three strokes were eventually connected to form a glyph resembling a with an additional stroke at the bottom: ३. The Indian digits spread to the Caliphate in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Octane Rating
An octane rating, or octane number, is a standard measure of a liquid fuel, fuel's ability to withstand Compression ratio, compression in an internal combustion engine without causing engine knocking. The higher the octane number, the more compression the fuel can withstand before detonating. Octane rating does not relate directly to the power output or the energy content of the fuel per unit mass or volume, but simply indicates the resistance to detonating under pressure without a spark. Whether a higher octane fuel improves or impairs an engine's performance depends on the design of the engine. In broad terms, fuels with a higher octane rating are used in higher-compression Petrol engine, gasoline engines, which may yield higher power for these engines. The added power in such cases comes from the way the engine is designed to compress the air/fuel mixture, and not directly from the rating of the gasoline. In contrast, fuels with lower octane (but higher cetane numbers) are idea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Model Railroader
''Model Railroader'' (''MR'') is an American magazine about the hobby of model railroading. Founded in 1934 by Al C. Kalmbach, it is published monthly by Firecrown Media of Chattanooga, Tennessee. Commonly found on newsstands and in libraries, it promotes itself as the oldest magazine of its type in the United States, although it is the long-standing competitor to '' Railroad Model Craftsman,'' which - originally named ''The Model Craftsman'' - predates MR by one year. ''MR'' is considered to be a general-interest hobby magazine, appealing to a wide range of hobbyists, rather than specializing in a particular scale, or facet of the hobby (such as prototype operations or scratch building and kitbashing). ''Model Railroader'' covers a variety of scales and modeling techniques for engines, rolling stock, right-of-way, structures, and scenery. It reviews products including ready-to-run models as well as kits, tools and supplies. The magazine presents blueprints and photographs of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
H0 Scale
HO or H0 is a rail transport modelling scale using a 1:87 scale (3.5 mm to 1 foot). It is the most popular scale of model railway in the world. The rails are spaced apart for modelling standard gauge tracks and trains in HO. The name HO comes from 1:87 scale being ''half'' that of O scale, which was originally the smallest of the series of older and larger 0, 1, 2 and 3 gauges introduced by Märklin around 1900. Rather than referring to the scale as "half-zero" or "H-zero", English-speakers have consistently pronounced it and have generally written it with the letters HO. In other languages it also remains written with the letter H and number 0 (zero); in German it is thus pronounced as . In Japan, many models are produced using 1:80 scale proportions (16.5mm track is still used). History After the First World War there were several attempts to introduce a model railway about half the size of 0 scale that would be more suitable for smaller home layouts and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Model Railroading
Railway modelling (UK, Australia, New Zealand, and Ireland) or model railroading (US and Canada) is a hobby in which rail transport systems are modelled at a reduced scale. The scale models include locomotives, rolling stock, streetcars, tracks, signalling, cranes, and landscapes including: countryside, roads, bridges, buildings, vehicles, harbors, urban landscape, model figures, lights, and features such as rivers, hills, tunnels, and canyons. The earliest model railways were the ' carpet railways' in the 1840s. The first documented model railway was the Railway of the Prince Imperial (French: Chemin de fer du Prince Impérial) built in 1859 by Emperor Napoleon III for his then 3-year-old son, also Napoleon, in the grounds of the Château de Saint-Cloud in Paris. It was powered by clockwork and ran in a figure-of-eight. Electric trains appeared around the start of the 20th century, but these were crude likenesses. Model trains today are more realistic, in addition to be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dmitri Shostakovich
Dmitri Dmitriyevich Shostakovich, group=n (9 August 1975) was a Soviet-era Russian composer and pianist who became internationally known after the premiere of his First Symphony in 1926 and thereafter was regarded as a major composer. Shostakovich achieved early fame in the Soviet Union, but had a complex relationship with its government. His 1934 opera '' Lady Macbeth of Mtsensk'' was initially a success but later condemned by the Soviet government, putting his career at risk. In 1948, his work was denounced under the Zhdanov Doctrine, with professional consequences lasting several years. Even after his censure was rescinded in 1956, performances of his music were occasionally subject to state interventions, as with his Thirteenth Symphony (1962). Nevertheless, Shostakovich was a member of the Supreme Soviet of the RSFSR (1947) and the Supreme Soviet of the Soviet Union (from 1962 until his death), as well as chairman of the RSFSR Union of Composers (1960–1968). Over ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
24 Preludes And Fugues (Shostakovich)
The 24 Preludes and Fugues, Op. 87 by Dmitri Shostakovich are a set of 24 musical pieces for solo piano, one in each of the major and minor keys of the chromatic scale. The cycle was composed in 1950 and 1951 while Shostakovich was in Moscow, and premiered by pianist Tatiana Nikolayeva in Leningrad in December 1952; it was published the same year. A complete performance takes approximately 2 hours and 32 minutes. It is one of several examples of music written in all major and/or minor keys. Form and structure Each piece is in two parts—a prelude and fugue—varying in pace, length and complexity (for example, Fugue No. 13 in F major is in five voices, while Fugue No. 9 in E major is in only two voices). The pieces proceed in relative major/minor pairs around the circle of fifths: first C major and A minor (prelude and fugue nos. 1 and 2), then to one sharp (G major, E minor), two sharps (D major, B minor), and so on, ending with D minor (1 flat). Chopin's 24 Preludes, Op ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Century (cricket)
In cricket, a century is a score of 100 or more runs in a single innings by a batter. The term is also included in "century partnership" which occurs when two batsmen add 100 runs to the team total when they are batting together. A century is regarded as a landmark score for batters and a player's number of centuries is generally recorded in their career statistics. Scoring a century is loosely equivalent in merit to a bowler taking a five-wicket haul, and is commonly referred to as a ton or hundred. Scores of more than 200 runs are still statistically counted as a century, although these scores are referred to as double (200–299 runs), triple (300–399 runs), and quadruple centuries (400–499 runs), and so on. Reaching 50 runs in an innings is known as a half-century. Scoring a century at Lord's cricket ground in London earns the batter a place on the Lord's honours boards. Earliest known centuries Centuries were uncommon until the late 19th century because of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
13 (number)
13 (thirteen) is the natural number following 12 (number), 12 and preceding 14 (number), 14. Folklore surrounding the number 13 appears in many cultures around the world: one theory is that this is due to the cultures employing lunar-solar calendars (there are approximately 12.41 lunations per solar year, and hence 12 "true months" plus a smaller, and often portentous, thirteenth month). This can be witnessed, for example, in the "Twelve Days of Christmas" of Western European tradition. In mathematics The number 13 is a prime number, happy number and a lucky number. It is a twin prime with 11 (number), 11, as well as a cousin prime with 17 (number), 17. It is the second of only 3 Wilson prime, Wilson primes: 5, 13, and 563 (number), 563. A 13-sided regular polygon is called a tridecagon. List of basic calculations In languages Grammar * In all Germanic languages, 13 is the first Compound (linguistics), compound number; the numbers 11 and 12 have their own names. * The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cricket In Australia
Cricket is the most popular sport in Australia at international, domestic and local levels. It is important culturally and regarded as a national sport (along with Australian rules football), and is widely played across the country, especially from the months of September to April. It was one of the first of Australia's mainstream sports to be established, having begun in the Colony of New South Wales as early as December 1803. The peak administrative body for both professional and amateur cricket is Cricket Australia. Ausplay in 2024 reports that 541,743 adults and 156,089 children play cricket in Australia. Less than a quarter of all players are female. Separately, official audience data shows that 93.6% of Australians watched at least some cricket on TV in 2010–11 calendar year. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graham's Number
Graham's number is an Large numbers, immense number that arose as an upper bound on the answer of a problem in the mathematical field of Ramsey theory. It is much larger than many other large numbers such as Skewes's number and Moser's number, both of which are in turn much larger than a googolplex. As with these, it is so large that the observable universe is far too small to contain an ordinary Numerical digit, digital representation of Graham's number, assuming that each digit occupies one Planck volume, possibly the smallest measurable space. But even the number of digits in this digital representation of Graham's number would itself be a number so large that its digital representation cannot be represented in the observable universe. Nor even can the number of digits of ''that'' number—and so forth, for a number of times far exceeding the total number of Planck volumes in the observable universe. Thus, Graham's number cannot be expressed even by physical universe-scale Tetrat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
