ISO 8601

Various groups of citizens of the Roman Empire adopted the week, especially those who had spent time in the eastern parts of the empire, such as Egypt, where the 7-day week was in use. Contemporaneously, Christians, following the biblical instruction, spread the week's use along with their religion. As the early Christians evolved from being Jewish to being a distinct group, various groups evolved from celebrating both the Jewish Sabbath (Saturday) and the first day or the Lord's Day (Sunday), to celebrating only Sunday. S ...

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Week, Week - Origin of the seven-day week, Week - Later use of the week, Week - Facts and figures, Week - Bibliography

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20th century - Science and technology. The assembly line and mass production of motor vehicles and other goods allowed manufacturers to produce more and cheaper products. This allowed the automobile to become the most important means of transportation. The invention of heavier-than-air flying machines and the jet engine allowed for the world to become "smaller". Space flight increased knowledge of the rest of the universe and allowed for global real-time communications via geosynchronous satellites ...

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20th century, 20th century - Overview, 20th century - Important developments, events and achievements, 20th century - Science and technology, 20th century - Wars and politics, 20th century - Culture and entertainment, 20th century - Disease and medicine, 20th century - Natural resources and the environment, 20th century - Significant people, 20th century - World leaders, 20th century - Scientists, 20th century - Humanities, 20th century - Business, 20th century - Aerospace pioneers, 20th century - Spiritual figures, 20th century - Artists, 20th century - Music, 20th century - Film, 20th century - Writers and poets, 20th century - Sports figures, 20th century - Decades and years

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In seventeenth century Europe, using Roman numerals for the year of publication for books was standard; there were many other places it was used as well. Publishers attempted to make the number easier to read by those more accustomed to Arabic positional numerals. On British title pages, there were often spaces between the groups of digits: M DCC LXI is one example. This may have come from the French, who separated the groups of digits with periods, as: M.DCC.LXI. or M. DCC. LXI. Notice the period at the end of the sequence; many foreign cou ...

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Roman numerals, Roman numerals - Origins, Roman numerals - Zero, Roman numerals - IIII or IV?, Roman numerals - Calendars and clocks, Roman numerals - XCIX or IC?, Roman numerals - Year in Roman numerals, Roman numerals - Other modern usage by English-speaking peoples, Roman numerals - Modern non-English speaking usage, Roman numerals - Alternate forms, Roman numerals - Table of Roman numerals, Roman numerals - Games

Read more here: » Roman numerals: Encyclopedia II - Roman numerals - Year in Roman numerals

Roman numerals remained in common use until about the 14th century, when they were replaced by Arabic numerals (thought to have been introduced to Europe from al-Andalus, by way of Arab traders and arithmetic treatises, around the 11th century). The use of Roman numerals today is mostly restricted to ordinal numbers, such as volumes or chapters in a book or the numbers identifying monarchs or popes (e.g. Elizabeth II, Benedict XVI, etc.). Sometimes the numerals are written using lower-case letters (thus: i, ii, iii, iv, etc.), particularly if numbering paragraphs ...

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Roman numerals, Roman numerals - Origins, Roman numerals - Zero, Roman numerals - IIII or IV?, Roman numerals - Calendars and clocks, Roman numerals - XCIX or IC?, Roman numerals - Year in Roman numerals, Roman numerals - Other modern usage by English-speaking peoples, Roman numerals - Modern non-English speaking usage, Roman numerals - Alternate forms, Roman numerals - Table of Roman numerals, Roman numerals - Games

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The above uses are customary for English-speaking countries. Although many of them are also maintained in other countries, those countries have additional uses for Roman numerals which are unknown in English-speaking regions. The French, the Portuguese, and the Spanish use capital Roman numerals to denote centuries. For example, 'XVIII' refers to the eighteenth century, so as to avoid confusion between the '18th century' and the '1800s'. (The Italians take the opposite approach, basing names of centuries on the digit ...

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Roman numerals, Roman numerals - Origins, Roman numerals - Zero, Roman numerals - IIII or IV?, Roman numerals - Calendars and clocks, Roman numerals - XCIX or IC?, Roman numerals - Year in Roman numerals, Roman numerals - Other modern usage by English-speaking peoples, Roman numerals - Modern non-English speaking usage, Roman numerals - Alternate forms, Roman numerals - Table of Roman numerals, Roman numerals - Games

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In the Middle Ages, Latin writers used a horizontal line above a particular numeral to represent one thousand times that numeral, and additional vertical lines on both sides of the numeral to denote one hundred times the number, as in these examples: I for one thousand V for five thousand |I| for one hundred thousand |See also:

Roman numerals, Roman numerals - Origins, Roman numerals - Zero, Roman numerals - IIII or IV?, Roman numerals - Calendars and clocks, Roman numerals - XCIX or IC?, Roman numerals - Year in Roman numerals, Roman numerals - Other modern usage by English-speaking peoples, Roman numerals - Modern non-English speaking usage, Roman numerals - Alternate forms, Roman numerals - Table of Roman numerals, Roman numerals - Games

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Rules regarding Roman numerals often state that a symbol representing 10x may not precede any symbol larger than 10x+1. For example, C cannot be preceded by I or V, only by X (or, of course, by a symbol representing a value larger than C). Thus, one should represent the number "ninety-nine" as XCIX, not as the "shortcut" IC. However, these rules are not universally followed. This 'problem' manifested in questions as to why 1999 was not written simply IMM or MIM ...

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Roman numerals, Roman numerals - Origins, Roman numerals - Zero, Roman numerals - IIII or IV?, Roman numerals - Calendars and clocks, Roman numerals - XCIX or IC?, Roman numerals - Year in Roman numerals, Roman numerals - Other modern usage by English-speaking peoples, Roman numerals - Modern non-English speaking usage, Roman numerals - Alternate forms, Roman numerals - Table of Roman numerals, Roman numerals - Games

Read more here: » Roman numerals: Encyclopedia II - Roman numerals - XCIX or IC?

The notation of Roman numerals has varied through the centuries. Originally, it was common to use IIII to represent "four", because IV represented the god Jove (and later YHWH). The subtractive notation (which uses IV instead of IIII) has become universally used only in modern times. For example, Forme of Cury, a manuscript from 1390, uses IX for "nine", but IIII for "four". Another document in the same manuscript, from 1381, uses IV and IX. A third document in the same manuscript uses both IIII and IV, and IX. Constructions such as IIX for ...

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Roman numerals, Roman numerals - Origins, Roman numerals - Zero, Roman numerals - IIII or IV?, Roman numerals - Calendars and clocks, Roman numerals - XCIX or IC?, Roman numerals - Year in Roman numerals, Roman numerals - Other modern usage by English-speaking peoples, Roman numerals - Modern non-English speaking usage, Roman numerals - Alternate forms, Roman numerals - Table of Roman numerals, Roman numerals - Games

Read more here: » Roman numerals: Encyclopedia II - Roman numerals - IIII or IV?

Among Christians (with the exception of seventh-day sabbatarians, such as the denominations listed above) Sunday is considered holy and often a day of rest and church-attendance. In orthodox Christian families and communities some activities are not done, e.g. working, doing something that requires somebody else to work such as buying goods or services (including the use of public transport), driving a car, gardening, washing a car, etc. Exceptions which are allowed are making use of religious services, and, usu ...

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Sunday, Sunday - The name Sunday, Sunday - Position during a week, Sunday - Common Sunday occurrences, Sunday - Named days, Sunday - Sunday in popular culture

Read more here: » Sunday: Encyclopedia II - Sunday - Common Sunday occurrences

In algebra it is traditional to order terms in a polynomial, by ordering the monomials in the indeterminates. This is fundamental, in order to have a normal form. Such matters are typically left implicit in discussion between humans, but must of course be dealt with exactly in computer algebra. In practice one has an alphabet of indeterminates X, Y, ... and orders all monomials formed from them by a variant of lexicographical order. For example if one decides to order the alphabet by< ...

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Lexicographical order, Lexicographical order - Case of multiple products, Lexicographical order - Monomials

Read more here: » Lexicographical order: Encyclopedia II - Lexicographical order - Monomials

In general, the number zero did not have its own Roman numeral, but the concept of zero as a number was well known by all medieval computists (responsible for calculating the date of Easter). They included zero (via the Latin word nulla meaning nothing) as one of nineteen epacts, or the age of the moon on March 22. The first three epacts were nullae, xi, and xxii (written in minuscule or lower case). The first known computist to use zero was Dionysius Exiguus in 525, but the concept of zero was no doubt well known earlier. Only one in ...

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Roman numerals, Roman numerals - Origins, Roman numerals - Zero, Roman numerals - IIII or IV?, Roman numerals - Calendars and clocks, Roman numerals - XCIX or IC?, Roman numerals - Year in Roman numerals, Roman numerals - Other modern usage by English-speaking peoples, Roman numerals - Modern non-English speaking usage, Roman numerals - Alternate forms, Roman numerals - Table of Roman numerals, Roman numerals - Games

Read more here: » Roman numerals: Encyclopedia II - Roman numerals - Zero

The "modern" Roman numerals, post-Victorian era, are shown below: An accurate way to write large numbers in Roman numerals is to handle first the thousands, then hundreds, then tens, then units. Example: the number 1988. One thousand is M, nine hundred is CM, eighty is LXXX, eight is VIII. Put it together: MCMLXXXVIII (ⅯⅭⅯⅬⅩⅩⅩⅤⅠⅠⅠ). Unicode has a number of characters specifically designated as Roman numerals, as part of the Number Forms range from U+216 ...

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Roman numerals, Roman numerals - Origins, Roman numerals - Zero, Roman numerals - IIII or IV?, Roman numerals - Calendars and clocks, Roman numerals - XCIX or IC?, Roman numerals - Year in Roman numerals, Roman numerals - Other modern usage by English-speaking peoples, Roman numerals - Modern non-English speaking usage, Roman numerals - Alternate forms, Roman numerals - Table of Roman numerals, Roman numerals - Games

Read more here: » Roman numerals: Encyclopedia II - Roman numerals - Table of Roman numerals

Continental Europeans use the hyphen to delineate parts within a written date. Germans and Slavs also used roman numerals for the month; 14‑vii‑1789, for example, is one way of writing the first Bastille Day, though this usage is rapidly falling out of favour. Plaques on the wall of the Moscow Kremlin are written this way. Usage of hyphens, as opposed to the slashes used in the English language, is specified for international standards. International standard ISO 8601, which was accepted as European Standard EN 28601 and in ...

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Hyphen, Hyphen - Rules and customs of usage, Hyphen - Examples of usage, Hyphen - Origin and history of the hyphen, Hyphen - Hyphens in computing, Hyphen - International Standard dates

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Big-endian numbers are easier to read when debugging a program. Some think they are less intuitive because the most significant byte is at the smaller address. Some think they are less confusing because the significance order is the same as the order of normal textual character strings in the computer, just as in non-computer text (see below). A person's preference usually is based both on which convention was studied first, ...

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Endianness, Endianness - Explanation, Endianness - Endianness in computers, Endianness - Logical and arithmetical description, Endianness - Portability issues, Endianness - Endianness in communications, Endianness - Endianness in date formats, Endianness - Discussion background etymology, Endianness - Example programming caveat

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In a Gregorian mean year there are exactly 365.2425 days, and thus exactly 52.1775 weeks (unlike the Julian year of 365.25 days, which does not contain a number of weeks represented by a finite decimal expansion). There are exactly 20871 weeks in 400 Gregorian years, so 25 December 1605 was a Sunday just like 25 December 2005. A system of Dominical letters has been used to determine the day of week in the Gregorian or the Julian calendar. ISO 8601 includes a numbering system for weeks; each week is associated with the year in w ...

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Week, Week - Origin of the seven-day week, Week - Later use of the week, Week - Facts and figures, Week - Bibliography

Read more here: » Week: Encyclopedia II - Week - Facts and figures

January 1 of any year whose number is a multiple of 400 is a Saturday. From this you can work out the day of the week of any date. See also: Days of the week Calculating the day of the week ...

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Gregorian calendar, Gregorian calendar - History, Gregorian calendar - Invention, Gregorian calendar - Beginning of the year, Gregorian calendar - Adoption outside of Roman Catholic nations, Gregorian calendar - Proleptic Gregorian calendar, Gregorian calendar - Confusion with British vs. American usage, Gregorian calendar - Difference between Gregorian and Julian calendar dates, Gregorian calendar - Months of the year, Gregorian calendar - Accuracy, Gregorian calendar - Calendar seasonal error, Gregorian calendar - Numerical facts, Gregorian calendar - Number of leap years starting on a given day of the week, Gregorian calendar - Days of the week, Gregorian calendar - Reference

Read more here: » Gregorian calendar: Encyclopedia II - Gregorian calendar - Days of the week

Endianness is simply illustrated by the different manners in which countries format calendar dates. For example, in the United States and a few other countries, dates are commonly formatted as Month; Day; Year (e.g. "May 24th, 2006" or "5/24/2006"). This is a middle-endian order. In most of the world's countries, including Europe except Sweden, Latvia and Hungary, dates are formatted as Day; Month; Year (e.g. "24th May, 200 ...

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Endianness, Endianness - Explanation, Endianness - Endianness in computers, Endianness - Logical and arithmetical description, Endianness - Portability issues, Endianness - Endianness in communications, Endianness - Endianness in date formats, Endianness - Discussion background etymology, Endianness - Example programming caveat

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In general, the NUXI problem is the problem of transferring data between computers with differing byte order. For example, the string "UNIX", packed with two bytes per 16-bit integer, might look like "NUXI" to a machine with a different "byte sex". The problem is caused by the difference in endianness. The problem was first discovered when porting an early version of Unix from PDP-11 (a middle-endian architecture) to an IBM Series 1 minicomputer (a big-endian architecture); upon startup, ...

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Endianness, Endianness - Explanation, Endianness - Endianness in computers, Endianness - Logical and arithmetical description, Endianness - Portability issues, Endianness - Endianness in communications, Endianness - Endianness in date formats, Endianness - Discussion background etymology, Endianness - Example programming caveat

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When a sequence of small units is used to form a larger ordinal value, convention must establish the order in which those smaller units are placed. This could be considered similar to the situation in different written languages, where some are written left to right, while others (such as Arabic and Hebrew) are written right to left. The decimal numbering is big endian when written using numbers, starting at the left with the highest order magnitude and progressing to smaller order magnitudes to the right. For example, the number 1234 starts with the thousands (in this case: one thousand) and continues through the hundreds ...

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Endianness, Endianness - Explanation, Endianness - Endianness in computers, Endianness - Logical and arithmetical description, Endianness - Portability issues, Endianness - Endianness in communications, Endianness - Endianness in date formats, Endianness - Discussion background etymology, Endianness - Example programming caveat

Read more here: » Endianness: Encyclopedia II - Endianness - Explanation

The twentieth century saw a remarkable shift in the way that vast numbers of people lived, as a result of technological, medical, social, ideological, and political innovations. Terms like ideology, world war, genocide, and nuclear war entered common usage and became an influence on the lives of everyday people. War reached an unprecedented scale and level of sophistication; in the Second World War (1939-1945) alone, approximately 57 million people died, mainly due to massive improvements in weaponry. The trends of mechanization of goods and ...

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20th century, 20th century - Overview, 20th century - Important developments events and achievements, 20th century - Science and technology, 20th century - Wars and politics, 20th century - Culture and entertainment, 20th century - Disease and medicine, 20th century - Natural resources and the environment, 20th century - Significant people, 20th century - World leaders, 20th century - Scientists, 20th century - Humanities, 20th century - Business, 20th century - Aerospace pioneers, 20th century - Spiritual figures, 20th century - Artists, 20th century - Music, 20th century - Film, 20th century - Writers and poets, 20th century - Sports figures, 20th century - Decades and years

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When leap years and common years are taken into account, there are a total of 14 possible Gregorian calendars. When different dates of Easter are also taken into account, there are a total of 70 possible Gregorian calendars. An average year is 365.2425 days = 52.1775 weeks = 8,765.82 hours = 525,949.2 minutes = 31,556,952 seconds. A common year is 365 days = 8,760 hours = 525,600 minutes = 31,536,000 seconds. A leap year is 366 days = 8,784 hours = 527,040 minutes = 31,622,400 seconds. (Some years may also contain one or two leap seconds which can be positive or negative.) See als ...

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Gregorian calendar, Gregorian calendar - History, Gregorian calendar - Invention, Gregorian calendar - Beginning of the year, Gregorian calendar - Adoption outside of Roman Catholic nations, Gregorian calendar - Proleptic Gregorian calendar, Gregorian calendar - Confusion with British vs. American usage, Gregorian calendar - Difference between Gregorian and Julian calendar dates, Gregorian calendar - Months of the year, Gregorian calendar - Accuracy, Gregorian calendar - Calendar seasonal error, Gregorian calendar - Numerical facts, Gregorian calendar - Number of leap years starting on a given day of the week, Gregorian calendar - Days of the week, Gregorian calendar - Reference

Read more here: » Gregorian calendar: Encyclopedia II - Gregorian calendar - Numerical facts

In the ASCII character encoding, the hyphen was encoded as character 45. Technically, this character is called the hyphen-minus, as it is also used as the minus sign and for dashes. In Unicode, this same character is encoded as U+002D so that Unicode remains compatible with ASCII. However, Unicode also encodes the hyphen and minus separately, as U+2010 ( ‐ ) and U+2212 ( − ), respectively, along with a series of dashes. Usage of the hyphen-minus character is discouraged where possib ...

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Hyphen, Hyphen - Rules and customs of usage, Hyphen - Examples of usage, Hyphen - Origin and history of the hyphen, Hyphen - Hyphens in computing, Hyphen - International Standard dates

Read more here: » Hyphen: Encyclopedia II - Hyphen - Hyphens in computing