Editing Abacus

{{short description|Calculating tool}}
{{Redirect|Abaci|the Turkish Surname |Abacı (disambiguation){{!}}Abacı|the medieval book|Liber Abaci|other uses|Abacus (disambiguation)}}
{{Use mdy dates|date=June 2013}}{{Use American English|date=May  2021}}

[[File:Abacus_(PSF).png|thumb|[[Bi-quinary coded decimal]]-like abacus representing {{formatnum:1352964708}}]]

An '''abacus''' ({{plural form}} '''abaci''' or '''abacuses'''), also called a '''counting frame''', is a [[hand]]-operated calculating tool which was used from ancient times in the [[ancient Near East]], Europe, China, and Russia, until the adoption of the [[Hindu–Arabic numeral system]].<ref name="Boyer253">{{harvnb|Boyer|Merzbach|1991|pp=252–253}}</ref> An abacus consists of a two-dimensional array of [[Sliding (motion)|slidable]] [[beads]] (or similar objects). In their earliest designs, the beads could be loose on a flat surface or sliding in grooves. Later the beads were made to slide on rods and built into a frame, allowing faster manipulation.

Each rod typically represents one [[Numerical digit|digit]] of a multi-digit [[number]] laid out using a [[positional numeral system]] such as [[base ten]] (though some cultures used different [[numerical base]]s). [[Roman Empire|Roman]] and [[East Asian]] abacuses use a system resembling [[bi-quinary coded decimal]], with a top deck (containing one or two beads) representing fives and a bottom deck (containing four or five beads) representing ones. [[Natural numbers]] are normally used, but some allow simple [[fraction]]al components (e.g. {{Fraction|1|2}}, {{Fraction|1|4}}, and {{Fraction|1|12}} in [[Roman abacus]]), and a [[decimal point]] can be imagined for [[fixed-point arithmetic]].

Any particular abacus design supports multiple methods to perform calculations, including [[addition]], [[subtraction]], [[multiplication]], [[Division (mathematics)|division]], and [[square root|square]] and [[cube root]]s. The beads are first arranged to represent a number, then are manipulated to perform a [[mathematical operation]] with another number, and their final position can be read as the result (or can be used as the starting number for subsequent operations).

In the ancient world, abacuses were a practical calculating tool. It was widely used in Europe as late as the 17th century, but fell out of use with the rise of [[Hindu–Arabic numeral system|decimal notation]]<ref>{{Cite web |date=2025-01-17 |title=Abacus {{!}} Definition, History, Origin, & Facts |url=https://www.britannica.com/technology/abacus-calculating-device |access-date=2025-01-30 |website=[[Encyclopædia Britannica]] |language=en}}</ref> and [[algorism]]ic methods. Although [[calculator]]s and [[computer]]s are commonly used today instead of abacuses, abacuses remain in everyday use in some countries. The abacus has an advantage of not requiring a [[writing implement]] and [[paper]] (needed for [[algorism]]) or an [[electric power source]]. Merchants, traders, and clerks in some parts of [[Eastern Europe]], Russia, China, and Africa use abacuses. The abacus remains in common use as a scoring system in non-[[Electronics|electronic]] table games. Others may use an abacus due to [[visual impairment]] that prevents the use of a calculator.<ref name="Boyer253" /> The abacus is still used to teach the fundamentals of [[mathematics]] to children in many countries such as Japan<ref>{{cite web |title=The Japan Society - Soroban: The Japanese Abacus |url=https://www.japansociety.org.uk/resource?resource=49 |website=www.japansociety.org.uk |access-date=17 January 2025}}</ref> and China.<ref>{{cite journal |last1=Gueudet |first1=Ghislaine |last2=Poisard |first2=Caroline |title=Design and use of curriculum resources for teachers and teacher educators: Example of the Chinese abacus at primary school |journal=International Journal of Educational Research |date=1 January 2019 |volume=93 |pages=68–78 |doi=10.1016/j.ijer.2018.10.007 |url=https://www.sciencedirect.com/science/article/abs/pii/S0883035518305421 |issn=0883-0355}}</ref>

==Etymology==
The word ''abacus'' dates to at least 1387&nbsp;AD when a [[Middle English]] work borrowed the word from [[Latin]] that described a sandboard abacus. The Latin word is derived from [[ancient Greek]] {{lang|grc|ἄβαξ}} ({{Transliteration|grc|abax}}) which means something without a base, and colloquially, any piece of rectangular material.<ref>{{harvnb|de Stefani|1909|p=2}}</ref><ref>{{harvnb|Gaisford|1962|p=2}}</ref><ref>{{harvnb|Lasserre|Livadaras|1976|p=4}}</ref>  Alternatively, without reference to ancient texts on etymology, it has been suggested that it means "a square tablet strewn with dust",<ref>{{harvnb|Klein|1966|p=1}}</ref> or "drawing-board covered with dust (for the use of mathematics)"<ref>{{harvnb|Onions|Friedrichsen|Burchfield|1967|p=2}}</ref> (the exact shape of the Latin perhaps reflects the [[Genitive case|genitive form]] of the Greek word, {{lang|grc|ἄβακoς}} (''{{Transliteration|grc|abakos}}'')). While the table strewn with dust definition is popular, some argue evidence is insufficient for that conclusion.<ref name="pull17">{{harvnb|Pullan|1968|p=17}}</ref>{{refn|group=nb|Both C. J. Gadd, a keeper of the Egyptian and Assyrian Antiquities at the [[British Museum]], and [[Jacob Levy]], a Jewish historian who wrote ''Neuhebräisches und chaldäisches wörterbuch über die Talmudim und Midraschim [Neuhebräisches and Chaldean dictionary on the Talmuds and Midrashi]'', disagree with the "dust table" theory.<ref name=pull17/>}} Greek {{lang|grc|ἄβαξ}} probably borrowed from a [[Northwest Semitic language]] like [[Phoenician language|Phoenician]], evidenced by a cognate with the [[Hebrew language|Hebrew]] word ''ʾābāq'' ({{Script/Hebrew|אבק}}), or "dust" (in the post-Biblical sense "sand used as a writing surface").<ref name="Etymology">{{harvnb|Huehnergard|2011|p=2}}</ref>

Both ''abacuses''<ref name = SOED>{{harvnb|Brown|1993|p=2}}</ref> and ''abaci''<ref name = SOED/> are used as plurals. The user of an abacus is called an ''abacist''.<ref>{{harvnb|Gove|1976|p=1}}</ref>

==History==

===Mesopotamia===
The [[Sumer]]ian abacus appeared between 2700 and 2300&nbsp;BC. It held a table of successive columns which delimited the successive orders of magnitude of their [[sexagesimal]] (base 60) number system.<ref>{{harvnb|Ifrah|2001|p=11}}</ref>

Some scholars point to a character in [[Akkadian language|Babylonian cuneiform]] that may have been derived from a representation of the abacus.<ref>{{harvnb|Crump|1992|p=188}}</ref> It is the belief of Old Babylonian<ref>{{harvnb|Melville|2001}}</ref> scholars, such as Ettore Carruccio, that Old Babylonians "seem to have used the abacus for the operations of addition and subtraction; however, this primitive device proved difficult to use for more complex calculations".<ref>{{harvnb|Carruccio|2006|p=14}}</ref>

===Egypt===
Greek historian [[Herodotus]] mentioned the abacus in [[Ancient Egypt]]. He wrote that the Egyptians manipulated the pebbles from right to left, opposite in direction to the Greek left-to-right method. Archaeologists have found ancient disks of various sizes that are thought to have been used as counters. However, wall depictions of this instrument are yet to be discovered.<ref name=Smith1>{{harvnb|Smith|1958|pp=157–160}}</ref>

===Persia===
At around 600&nbsp;BC, Persians first began to use the abacus, during the [[Achaemenid Empire]].<ref>{{harvnb|Carr|2014}}</ref> Under the [[Parthian Empire|Parthian]], [[Sassanian]], and [[Iran]]ian empires, scholars concentrated on exchanging knowledge and inventions with the countries around them – India, China, and the [[Roman Empire]] – which is how the abacus may have been exported to other countries.

=== Greece ===
[[Image:Salaminische Tafel Salamis Tablet nach Wilhelm Kubitschek Numismatische Zeitschrift Bd 31 Wien 1899 p.&nbsp;394 ff.jpg|thumb|upright|An early photograph of the Salamis Tablet, 1899. The original is marble and is held by the National Museum of Epigraphy, in Athens.]]
The earliest archaeological evidence for the use of the Greek abacus dates to the 5th century BC.<ref>{{harvnb|Ifrah|2001|p=15}}</ref> [[Demosthenes]] (384–322 BC) complained that the need to use pebbles for calculations was too difficult.<ref name=Will/><ref name=pull>{{harvnb|Pullan|1968|p=16}}</ref> A play by [[Alexis (poet)|Alexis]] from the 4th century BC mentions an abacus and pebbles for accounting, and both [[Diogenes]] and [[Polybius]] use the abacus as a metaphor for human behavior, stating "that men that sometimes stood for more and sometimes for less" like the pebbles on an abacus.<ref name=pull/> The Greek abacus was a table of wood or marble, pre-set with small counters in wood or metal for mathematical calculations.<ref name=":1" /> This Greek abacus was used in Achaemenid Persia, the [[Etruscan civilization]], Ancient Rome, and the Western Christian world until the [[French Revolution]].

The [[Salamis Tablet]], found on the Greek island [[Salamis Island|Salamis]] in 1846&nbsp;AD, dates to 300&nbsp;BC, making it the oldest counting board discovered so far. It is a slab of white marble {{convert|149|cm|0|abbr=on}} in length, {{convert|75|cm|0|abbr=on}} wide, and {{convert|4.5|cm|0|abbr=on}} thick, on which are 5 groups of markings. In the tablet's center is a set of 5 parallel lines equally divided by a vertical line, capped with a semicircle at the intersection of the bottom-most horizontal line and the single vertical line. Below these lines is a wide space with a horizontal crack dividing it. Below this crack is another group of eleven parallel lines, again divided into two sections by a line perpendicular to them, but with the semicircle at the top of the intersection; the third, sixth and ninth of these lines are marked with a cross where they intersect with the vertical line.<ref>{{harvnb|Williams|1997|pp=55–56}}</ref> Also from this time frame, the [[Darius Vase]] was unearthed in 1851. It was covered with pictures, including a "treasurer" holding a wax tablet in one hand while manipulating counters on a table with the other.<ref name="Will"/>

=== Rome ===
{{Main|Roman abacus}}
[[File:RomanAbacusRecon.jpg|right|thumb|Copy of a [[Roman abacus]]]]
The normal method of calculation in ancient Rome, as in Greece, was by moving counters on a smooth table. Originally pebbles ({{Langx|la|calculi}}) were used. Marked lines indicated units, fives, tens, etc. as in the [[Roman numeral]] system.

Writing in the 1st century BC, [[Horace]] refers to the wax abacus, a board covered with a thin layer of black wax on which columns and figures were inscribed using a stylus.<ref name=rome>{{harvnb|Ifrah|2001|p=18}}</ref>

One example of archaeological evidence of the [[Roman abacus]], shown nearby in reconstruction, dates to the 1st century AD. It has eight long grooves containing up to five beads in each and eight shorter grooves having either one or no beads in each. The groove marked I indicates units, X tens, and so on up to millions. The beads in the shorter grooves denote fives (five units, five tens, etc.) resembling a [[bi-quinary coded decimal]] system related to the [[Roman numerals]]. The short grooves on the right may have been used for marking Roman "ounces" (i.e. fractions).

=== Medieval Europe ===

The Roman system of 'counter casting' was used widely in medieval Europe, and persisted in limited use into the nineteenth century.<ref name=":1">{{harvnb|Pullan|1968|p=13}}</ref> Wealthy abacists used decorative minted counters, called [[jeton]]s.

Due to [[Pope Sylvester II]]'s reintroduction of the abacus with modifications, it became widely used in Europe again during the 11th century<ref>{{harvnb|Brown|2010|pp=81–82}}</ref><ref>{{harvnb|Brown|2011}}</ref> It used beads on wires, unlike the traditional Roman counting boards, which meant the abacus could be used much faster and was more easily moved.<ref>{{harvnb|Huff|1993|p=50}}</ref>

===China===
{{Main|Suanpan}}
[[File:abacus 6.png|thumb|A Chinese abacus (''[[suanpan]]'') (the number represented in the picture is 6,302,715,408)]]
{{Infobox Chinese
|t=算盤
|s=算盘
|l="calculating tray"
|p=suànpán
|mi={{IPAc-cmn|s|uan|4|.|p|an|2}}
|j=syun<sup>3</sup>-pun<sup>4</sup>
|y=syun-pùhn
|ci={{IPAc-yue|s|yun|3|p|un|2}}
|poj=sǹg-pôaⁿ
|tl=sǹg-puânn
}}
The earliest known written documentation of the Chinese abacus dates to the 2nd century BC.<ref>{{harvnb|Ifrah|2001|p=17}}</ref>

The Chinese abacus, also known as the ''[[suanpan]]'' (算盤/算盘, lit. "calculating tray"), comes in various lengths and widths, depending on the operator. It usually has more than seven rods. There are two beads on each rod in the upper deck and five beads each in the bottom one, to represent numbers in a [[bi-quinary coded decimal]]-like system. The beads are usually rounded and made of [[hardwood]]. The beads are counted by moving them up or down towards the beam; beads moved toward the beam are counted, while those moved away from it are not.<ref name="Ryerson">{{harvnb|Fernandes|2003}}</ref> One of the top beads is 5, while one of the bottom beads is 1. Each rod has a number under it, showing the place value. The ''suanpan'' can be reset to the starting position instantly by a quick movement along the horizontal axis to spin all the beads away from the horizontal beam at the center.

The prototype of the Chinese abacus appeared during the [[Han dynasty]], and the beads are oval. The [[Song dynasty]] and earlier used the 1:4 type or four-beads abacus similar to the modern abacus including the shape of the beads commonly known as Japanese-style abacus.<ref>{{Cite web |title=Difference Between Chinese and Japanese Abacus |url=https://abakus-center.com/blog/chinese-and-japanese-abacus |access-date=2024-05-29 |website=Abakus Europe |language=en}}</ref>

In the early [[Ming dynasty]], the abacus began to appear in a 1:5 ratio. The upper deck had one bead and the bottom had five beads.<ref name=":0">{{Cite web|date=August 22, 2020|title=中国算盘 {{!}} 清华大学科学博物馆|url=http://tsm.tsinghua.edu.cn/?p=2769|url-status=live|access-date=August 8, 2021|website=Department of the History of Science, Tsinghua University|language=zh|archive-url=https://web.archive.org/web/20210808105557/http://tsm.tsinghua.edu.cn/?p=2769 |archive-date=August 8, 2021 }}</ref> In the late Ming dynasty, the abacus styles appeared in a 2:5 ratio.<ref name=":0" />  The upper deck had two beads, and the bottom had five.

Various calculation techniques were devised for ''Suanpan'' enabling efficient calculations. Some schools teach students how to use it.

In the long scroll ''[[Along the River During the Qingming Festival]]'' painted by [[Zhang Zeduan]] during the [[Song dynasty]] (960–1297), a ''suanpan'' is clearly visible beside an account book and doctor's prescriptions on the counter of an [[apothecary]]'s (Feibao).

The similarity of the [[Roman abacus]] to the Chinese one suggests that one could have inspired the other, given evidence of a trade relationship between the [[Roman Empire]] and China. However, no direct connection has been demonstrated, and the similarity of the abacuses may be coincidental, both ultimately arising from counting with five fingers per hand. Where the Roman model (like most modern Korean and [[#Japan|Japanese]]) has 4 plus 1 bead per decimal place, the standard ''suanpan'' has 5 plus 2. Incidentally, this ancient [[Chinese units of measurement|Chinese calculation system]] 市用制 (''Shì yòng zhì'') allows use with a [[hexadecimal]] numeral system (or any [[Radix|base]] up to 18) which is used for traditional Chinese measures of weight [(''jīn'' (斤) and ''liǎng'' (兩)]. (Instead of running on wires as in the Chinese, Korean, and Japanese models, the Roman model used grooves, presumably making arithmetic calculations much slower).

Another possible source of the ''suanpan'' is Chinese [[counting rods]], which operated with a [[decimal|decimal system]] but lacked the concept of [[0 (number)|zero]] as a placeholder.{{citation needed|date=April 2024}} The zero was probably introduced to the Chinese in the [[Tang dynasty]] (618–907) when travel in the Indian Ocean and the [[Middle East]] would have provided direct contact with India, allowing them to acquire the concept of zero and the [[decimal point]] from Indian merchants and mathematicians.{{citation needed|date=April 2024}}

===India===

The ''[[Abhidharmakośabhāṣya]]'' of [[Vasubandhu]] (316–396), a Sanskrit work on [[Buddhist philosophy]], says that the second-century CE philosopher [[Vasumitra]] said that "placing a wick (Sanskrit ''vartikā'') on the number one (''ekāṅka'') means it is a one while placing the wick on the number hundred means it is called a hundred, and on the number one thousand means it is a thousand".  It is unclear exactly what this arrangement may have been. Around the 5th century, Indian clerks were already finding new ways of recording the contents of the abacus.<ref>{{harvnb|Körner|1996|p=232}}</ref> Hindu texts used the term ''śūnya'' (zero) to indicate the empty column on the abacus.<ref>{{harvnb|Mollin|1998|p=3}}</ref>

===Japan===
{{Main|Soroban}}
[[File:Soroban.JPG|thumb|Japanese [[soroban]]]]
In Japan, the abacus is called ''[[soroban]]'' ({{lang|ja|算盤, そろばん}}, lit. "counting tray"). It was imported from China in the 14th century.<ref name=Gul>{{harvnb|Gullberg|1997|p=169}}</ref> It was probably in use by the working class a century or more before the ruling class adopted it, as the class structure obstructed such changes.<ref>{{harvnb|Williams|1997|p=65}}</ref> The 1:4 abacus, which removes the seldom-used second and fifth bead, became popular in the 1940s.

Today's Japanese abacus is a 1:4 type, four-bead abacus, introduced from China in the [[Muromachi period|Muromachi era]]. It adopts the form of the upper deck one bead and the bottom four beads. The top bead on the upper deck was equal to five and the bottom one is similar to the Chinese or Korean abacus, and the decimal number can be expressed, so the abacus is designed as a 1:4 device. The beads are always in the shape of a diamond. The quotient division is generally used instead of the division method; at the same time, in order to make the multiplication and division digits consistently use the division multiplication. Later, Japan had a 3:5 abacus called 天三算盤, which is now in the Ize Rongji collection of Shansi Village in [[Yamagata, Yamagata|Yamagata]] City. Japan also used a 2:5 type abacus.

The four-bead abacus spread, and became common  around the world. Improvements to the Japanese abacus arose in various places. In China, an abacus with an aluminium frame and plastic beads has been used. The file is next to the four beads, and pressing the "clearing" button puts the upper bead in the upper position, and the lower bead in the lower position.

The abacus is still manufactured in Japan, despite the proliferation, practicality, and affordability of pocket [[electronic calculator]]s. The use of the soroban is still taught in Japanese [[primary school]]s as part of [[mathematics]], primarily as an aid to faster mental calculation. Using visual imagery, one can complete a calculation as quickly as with a physical instrument.<ref>{{harvnb|Murray|1982}}</ref>

===Korea===
The Chinese abacus migrated from China to [[Korea]] around 1400&nbsp;AD.<ref name=Will>{{harvnb|Williams|1997|p=55}}</ref><ref name="thocp">{{harvnb|Anon|2002}}</ref><ref>{{harvnb|Jami|1998|p=4}}</ref> Koreans call it ''jupan'' (주판), ''supan'' (수판) or ''jusan'' (주산).<ref>{{harvnb|Anon|2013}}</ref> The four-beads abacus (1:4) was introduced during the [[Goryeo|Goryeo Dynasty]]. The 5:1 abacus was introduced to Korea from China during the Ming Dynasty.

===Native America===
[[File:Quipu.png|thumb|Representation of an [[Inca]] [[quipu]]]]
[[File:Yupana 1.png|thumb|A [[yupana]] as used by the Incas]]
Some sources mention the use of an abacus called a ''nepohualtzintzin'' in ancient [[Aztec]] culture.<ref>{{harvnb|Sanyal|2008}}</ref> This [[Mesoamerica]]n abacus used a 5-digit base-20 system.<ref>{{harvnb|Anon|2004}}</ref> The word Nepōhualtzintzin {{IPA|nah|nepoːwaɬˈt͡sint͡sin}} comes from [[Nahuatl]], formed by the roots; ''Ne'' – personal -; ''pōhual'' or ''pōhualli'' {{IPA|nah|ˈpoːwalːi}} – the account -; and ''tzintzin'' {{IPA|nah|ˈt͡sint͡sin}} – small similar elements. Its complete meaning was taken as: counting with small similar elements. Its use was taught in the [[Calmecac]] to the ''temalpouhqueh'' {{IPA|nah|temaɬˈpoʍkeʔ}}, who were students dedicated to taking the accounts of skies, from childhood.

The Nepōhualtzintzin was divided into two main parts separated by a bar or intermediate cord. In the left part were four beads. Beads in the first row have unitary values (1, 2, 3, and 4), and on the right side,  three beads had values of 5, 10, and 15, respectively. In order to know the value of the respective beads of the upper rows, it is enough to multiply by 20 (by each row), the value of the corresponding count in the first row.

The device featured 13 rows with 7 beads, 91 in total. This was a basic number for this culture. It had a close relation to natural phenomena, the underworld, and the cycles of the heavens. One Nepōhualtzintzin (91) represented the number of days that a season of the year lasts, two Nepōhualtzitzin (182) is the number of days of the corn's cycle, from its sowing to its harvest, three Nepōhualtzintzin (273) is the number of days of a baby's gestation, and four Nepōhualtzintzin (364) completed a cycle and approximated one year. When translated into modern computer arithmetic, the Nepōhualtzintzin amounted to the rank from 10 to 18 in [[floating point]], which precisely calculated large and small amounts, although round off was not allowed.

The rediscovery of the Nepōhualtzintzin was due to the Mexican engineer David Esparza Hidalgo,<ref>{{harvnb|Hidalgo|1977|p=94}}</ref> who in his travels throughout Mexico found diverse engravings and paintings of this instrument and reconstructed several of them in gold, jade, encrustations of shell, etc.<ref>{{harvnb|Hidalgo|1977|pp=94–101}}</ref> Very old Nepōhualtzintzin are attributed to the [[Olmec]] culture, and some bracelets of [[Maya peoples|Maya]]n origin, as well as a diversity of forms and materials in other cultures.

Sanchez wrote in ''Arithmetic in Maya'' that another base 5, base 4 abacus had been found in the [[Yucatán Peninsula]] that also computed calendar data. This was a finger abacus, on one hand, 0, 1, 2, 3, and 4 were used; and on the other hand 0, 1, 2, and 3 were used. Note the use of zero at the beginning and end of the two cycles.

The [[quipu]] of the [[Inca]]s was a system of colored knotted cords used to record numerical data,<ref>{{harvnb|Albree|2000|p=42}}</ref> like advanced [[tally stick]]s – but not used to perform calculations. Calculations were carried out using a [[yupana]] ([[Quechua languages|Quechua]] for "counting tool"; see figure) which was still in use after the conquest of Peru. The working principle of a yupana is unknown, but in 2001 Italian mathematician De Pasquale proposed an explanation. By comparing the form of several yupanas, researchers found that calculations were based using the [[Fibonacci sequence]] 1, 1, 2, 3, 5 and powers of 10, 20, and 40 as place values for the different fields in the instrument. Using the Fibonacci sequence would keep the number of grains within any one field at a minimum.<ref>{{harvnb|Aimi|De Pasquale|2005}}</ref>

===Russia===
[[File:Schoty abacus.jpg|thumb|Russian schoty]]
The Russian abacus, the ''schoty'' ({{Langx|ru|счёты}}, plural from {{Langx|ru|счёт}}, counting), usually has a single slanted deck, with ten beads on each wire (except one wire with four beads for quarter-[[ruble]] fractions). 4-bead wire was introduced for quarter-[[Russian ruble|kopek]]s, which were minted until 1916.<ref>{{Cite journal |last1=Sokolov |first1=Viatcheslav |last2=Karelskaia |first2=Svetlana |last3=Zuga |first3=Ekaterina |date=February 2023 |title=The schoty (abacus) as the phenomenon of Russian accounting |url=http://journals.sagepub.com/doi/10.1177/10323732221132005 |journal=Accounting History |language=en |volume=28 |issue=1 |pages=90–118 |doi=10.1177/10323732221132005 |s2cid=256789240 |issn=1032-3732}}</ref> The Russian abacus is used vertically, with each wire running horizontally. The wires are usually bowed upward in the center, to keep the beads pinned to either side. It is cleared when all the beads are moved to the right. During manipulation, beads are moved to the left. For easy viewing, the middle 2 beads on each wire (the 5th and 6th bead) usually are of a different color from the other eight. Likewise, the left bead of the thousands wire (and the million wire, if present) may have a different color.

The Russian abacus was in use in shops and markets throughout the [[Commonwealth of Independent States|former Soviet Union]], and its usage was taught in most schools until the 1990s.<ref>{{harvnb|Burnett|Ryan|1998|p=7}}</ref><ref>{{harvnb|Hudgins|2004|p=219}}</ref> Even the 1874 invention of [[mechanical calculator]], [[Odhner Arithmometer|Odhner arithmometer]], had not replaced them in Russia. According to [[Yakov Perelman]], some businessmen attempting to import calculators into the Russian Empire were known to leave in despair after watching  a skilled abacus operator.<ref>''Arithmetic for Entertainment'', [[Yakov Perelman]], page 51.</ref> Likewise, the mass production of Felix [[arithmometer]]s since 1924 did not significantly reduce abacus use in the [[Soviet Union]].<ref>{{harvnb|Leushina|1991|p=427}}</ref> The Russian abacus began to lose popularity only after the mass production of domestic [[Pocket calculator|microcalculators]] in 1974.<ref>{{Cite journal |date=1975 |title=The Abacus Today |url=https://www.jstor.org/stable/30211432 |journal=Mathematics in School |volume=4 |issue=5 |pages=18–19 |jstor=30211432 |issn=0305-7259}}</ref>

The Russian abacus was brought to France around 1820 by mathematician [[Jean-Victor Poncelet]], who had served in [[Napoleon]]'s army and had been a [[prisoner of war]] in Russia.<ref>{{harvnb|Trogeman|Ernst|2001|p=24}}</ref> To Poncelet's French contemporaries, it was something new. Poncelet used it, not for any applied purpose, but as a teaching and demonstration aid.<ref>{{harvnb|Flegg|1983|p=72}}</ref> The [[Turkic peoples|Turks]] and the [[Armenians|Armenian]] people used abacuses similar to the Russian schoty. It was named a ''coulba'' by the Turks and a ''choreb'' by the Armenians.<ref>{{harvnb|Williams|1997|p=64}}</ref>

==School abacus==
[[File:Kugleramme.jpg|thumb|Early 20th century abacus used in Danish elementary school]]
[[File:Telraam.JPG|thumb|A twenty bead ''rekenrek'']]
Around the world, abacuses have been used in pre-schools and elementary schools as an aid in teaching the [[numeral system]] and [[arithmetic]].

In Western countries, a bead frame similar to the Russian abacus but with straight wires and a vertical frame is common (see image).

Each bead represents one unit (e.g. 74 can be represented by shifting all beads on 7 wires and 4 beads on the 8th wire, so numbers up to 100 may be represented). In the bead frame shown, the gap between the 5th and 6th wire, corresponding to the color change between the 5th and the 6th bead on each wire, suggests the latter use. Teaching multiplication, e.g. 6 times 7, may be represented by shifting 7 beads on 6 wires.

The red-and-white abacus is used in contemporary primary schools for a wide range of number-related lessons. The twenty bead version, referred to by its [[Dutch language|Dutch]] name ''rekenrek'' ("calculating frame"), is often used, either on a string of beads or on a rigid framework.<ref>{{harvnb|West|2011|p=49}}</ref>

== Neurological analysis ==
Learning how to calculate with the abacus may improve capacity for mental calculation. [[Mental abacus|Abacus-based mental calculation]] (AMC), which was derived from the abacus, is the act of performing calculations, including addition, subtraction, multiplication, and division, in the mind by manipulating an imagined abacus. It is a high-level cognitive skill that runs calculations with an effective algorithm. People doing long-term AMC training show higher numerical memory capacity and experience more effectively connected neural pathways.<ref>{{Cite journal|last1=Hu|first1=Yuzheng|last2=Geng|first2=Fengji|last3=Tao|first3=Lixia|last4=Hu|first4=Nantu|last5=Du|first5=Fenglei|last6=Fu|first6=Kuang|last7=Chen|first7=Feiyan|date=2010-12-14|title=Enhanced white matter tracts integrity in children with abacus training|journal=Human Brain Mapping|language=en|volume=32|issue=1|pages=10–21|doi=10.1002/hbm.20996|pmid=20235096|issn=1065-9471|pmc=6870462}}</ref><ref>{{Cite journal|last1=Wu|first1=Tung-Hsin|last2=Chen|first2=Chia-Lin|last3=Huang|first3=Yung-Hui|last4=Liu|first4=Ren-Shyan|last5=Hsieh|first5=Jen-Chuen|last6=Lee|first6=Jason J. S.|s2cid=9860036|date=2008-11-05|title=Effects of long-term practice and task complexity on brain activities when performing abacus-based mental calculations: a PET study|journal=European Journal of Nuclear Medicine and Molecular Imaging|language=en|volume=36|issue=3|pages=436–445|doi=10.1007/s00259-008-0949-0|pmid=18985348|issn=1619-7070}}</ref> They are able to retrieve memory to deal with complex processes.<ref>{{Cite book |doi=10.1109/CNE.2003.1196886 |chapter=Brain activation during abacus-based mental calculation with fMRI: A comparison between abacus experts and normal subjects |title=First International IEEE EMBS Conference on Neural Engineering, 2003. Conference Proceedings |pages=553–556 |year=2003 |last1=Lee |first1=J.S. |last2=Chen |first2=C.L. |last3=Wu |first3=T.H. |last4=Hsieh |first4=J.C. |last5=Wui |first5=Y.T. |last6=Cheng |first6=M.C. |last7=Huang |first7=Y.H. |s2cid=60704352 |isbn=978-0-7803-7579-6 }}</ref> AMC involves both [[Visuospatial function|visuospatial]] and visuomotor processing that generate the visual abacus and move the imaginary beads.<ref name=":022">{{Cite journal|date=2006-12-20|title=Prospective demonstration of brain plasticity after intensive abacus-based mental calculation training: An fMRI study|journal=Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment|language=en|volume=569|issue=2|pages=567–571|doi=10.1016/j.nima.2006.08.101|issn=0168-9002|last1=Chen|first1=C.L.|last2=Wu|first2=T.H.|last3=Cheng|first3=M.C.|last4=Huang|first4=Y.H.|last5=Sheu|first5=C.Y.|last6=Hsieh|first6=J.C.|last7=Lee|first7=J.S.|bibcode=2006NIMPA.569..567C}}</ref> Since it only requires that the final position of beads be remembered, it takes less memory and less computation time.<ref name=":022" />{{Clear}}

==Renaissance abacuses ==
<gallery>
File:Houghton Typ 520.03.736 - Margarita philosophica.jpg
File:Rechentisch.png
File:Rechnung auff der Linihen und Federn.JPG
File:Köbel Böschenteyn 1514.jpg
File:Rechnung auff der linihen 1525 Adam Ries.PNG
File:1543 Robert Recorde.PNG
File:Peter Apian 1544.PNG
File:Adam riesen.jpg
File:Rekenaar 1553.jpg
</gallery>

==Binary abacus==
[[File:Bbinary Abacus 002.jpg|thumb|Two binary abacuses constructed by Robert C. Good Jr., made from two Chinese abacuses]]
The binary abacus is used to explain how computers manipulate numbers.<ref>{{harvnb|Good|1985|p=34}}</ref> The abacus shows how numbers, letters, and signs can be stored in a [[binary number|binary system]] on a computer, or via [[ASCII]]. The device consists of beads on parallel wires arranged in three rows; each bead represents a switch which can be either  "on" or "off".

==Visually impaired users==
An adapted abacus, invented by Tim Cranmer, and called a Cranmer abacus is commonly used by visually impaired users. A piece of soft fabric or rubber is placed behind the beads, keeping them in place while the users manipulate them. The device is then used to perform the mathematical functions of multiplication, division, addition, subtraction, square root, and cube root.<ref name="aph">{{harvnb|Terlau|Gissoni|2005}}</ref>

Although blind students have benefited from talking calculators, the abacus is often taught to these students in early grades.<ref>{{harvnb|Presley|D'Andrea|2009}}</ref> Blind students can also complete mathematical assignments using a braille-writer and [[Nemeth Braille|Nemeth code]] (a type of braille code for mathematics) but large multiplication and [[long division]] problems are tedious. The abacus gives these students a tool to compute mathematical problems that equals the speed and mathematical knowledge required by their sighted peers using pencil and paper. Many blind people find this number machine a useful tool throughout life.<ref name="aph" />

==See also==
* [[Chinese Zhusuan]]
* [[Chisanbop]]
* [[Logical abacus]]
* [[Napier's bones]]
* [[Sand table]]
* [[Slide rule]]

==Notes==
{{reflist|group=nb}}

==Footnotes==
{{reflist|30em}}

==References==
{{Refbegin|35em}}
* {{cite web |last1=Aimi |first1=Antonio |last2=De Pasquale |first2=Nicolino |others=translated by Del Bianco, Franca |url=http://www.quipus.it/english/Andean%20Calculators.pdf |title=Andean Calculators |year=2005 |access-date=July 31, 2014 |archive-date=May 3, 2015 |archive-url=https://web.archive.org/web/20150503005239/http://www.quipus.it/english/Andean%20Calculators.pdf |url-status=live |df=mdy }}
* {{cite encyclopedia | last = Albree | first = Joe | editor-last = Hessenbruch | editor-first = Arne |title = Reader's Guide to the History of Science | isbn = 978-1-884964-29-9 | year = 2000 | publisher = Fitzroy Dearborn Publishers | location = London, UK }}
* {{cite web |author=Anon |url=http://www.thocp.net/hardware/abacus.html |title=Abacus middle ages, region of origin Middle East |website=The History of Computing Project |date=September 12, 2002 |access-date=July 31, 2014 |archive-date=May 9, 2014 |archive-url=https://web.archive.org/web/20140509093935/http://www.thocp.net/hardware/abacus.html |url-status=live |df=mdy }}
* {{cite web |author=Anon |url=http://www.inaoep.mx/iberamia2004/nepo_eng.htm |title=Nepohualtzintzin, The Pre Hispanic Computer |year=2004 |website=Iberamia 2004 |archive-date=May 3, 2015 |archive-url=https://web.archive.org/web/20150503004718/http://www.inaoep.mx/iberamia2004/nepo_eng.htm |access-date=July 31, 2014 |url-status=live |df=mdy }}
* {{cite web |author=Anon |url=http://enc.daum.net/dic100/contents.do?query1=b19j3727a |script-title=ko:주판 |trans-title=Abacus |language=ko |website=enc.daum.net |year=2013 |access-date=July 31, 2014 |archive-date=July 7, 2012 |archive-url=https://archive.today/20120707220016/http://100.daum.net/encyclopedia/view.do?docid=b19j3727a |url-status=live |df=mdy }}
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* {{cite book | last = Brown | first = Nancy Marie | url = https://books.google.com/books?id=vwy5B9ZXMh4C | title = The Abacus and the Cross: The Story of the Pope Who Brought the Light of Science to the Dark Ages | year = 2010 | publisher = Basic Books | location = Philadelphia, PA | isbn = 978-0-465-00950-3 }}
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* {{cite web | last = Fernandes | first = Luis | url = http://www.ee.ryerson.ca:8080/~elf/abacus/intro.html | title = A Brief Introduction to the Abacus | date = November 27, 2003 | work = ee.ryerson.ca | access-date = July 31, 2014 | archive-url = https://web.archive.org/web/20141226170451/http://www.ee.ryerson.ca:8080/~elf/abacus/intro.html | archive-date = December 26, 2014 | url-status = dead }}
* {{cite book | last = Flegg | first = Graham | title = Numbers: Their History and Meaning | publisher = Courier Dover Publications | year = 1983 | series = Dover Books on Mathematics | isbn = 978-0-233-97516-0 | location = Mineola, NY }}
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* {{cite journal | last = Good | first = Robert C. Jr.| title = The Binary Abacus: A Useful Tool for Explaining Computer Operations | journal = Journal of Computers in Mathematics and Science Teaching | volume = 5 | issue = 1 | pages = 34–37 | date = Fall 1985 }}
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* {{cite book | last = Hudgins | first = Sharon | title = The Other Side of Russia: A Slice of Life in Siberia and the Russian Far East | series = Eugenia & Hugh M. Stewart '26 Series on Eastern Europe | publisher = Texas A&M University Press | year = 2004 | isbn = 978-1-58544-404-5 }}
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* {{cite encyclopedia | editor-last = Klein | editor-first = Ernest | title = abacus | encyclopedia = A Comprehensive Etymological Dictionary of the English Language | publisher = Elsevier Publishing Company | location = Amsterdam | year = 1966 | volume = I: A-K }}
* {{cite book | last = Körner | first = Thomas William | title = The Pleasures of Counting | publisher = Cambridge University Press | location = Cambridge, UK | year = 1996 | isbn = 978-0-521-56823-4 | url-access = registration | url = https://archive.org/details/pleasuresofcount0000korn }}
* {{cite book | editor1-last = Lasserre | editor1-first = Franciscus | editor2-last = Livadaras | editor2-first = Nicolaus | publisher = Edizioni dell'Ateneo | location = Rome, Italy | title = Etymologicum Magnum Genuinum: Symeonis Etymologicum: Una Cum Magna Grammatica | lccn = 77467964 | year = 1976 | volume = Primum: α — άμωσϒέπωϛ | language = el, la }}
* {{cite book | last = Leushina | first = A. M. | title = The development of elementary mathematical concepts in preschool children | publisher = National Council of Teachers of Mathematics | year = 1991 | isbn = 978-0-87353-299-0 }}
* {{cite web |last=Melville |first=Duncan J. |url=http://it.stlawu.edu/~dmelvill/mesomath/chronology.html |title=Chronology of Mesopotamian Mathematics |publisher=It.stlawu.edu |date=May 30, 2001 |access-date=Jun 19, 2014 |archive-date=January 12, 2014 |archive-url=https://web.archive.org/web/20140112180918/http://it.stlawu.edu/%7Edmelvill/mesomath/chronology.html |website=[[St. Lawrence University]] |url-status=live |df=mdy }}
* {{cite encyclopedia | editor-last = Mish | editor-first = Frederick C. | publisher = Merriam-Webster, Inc | title = abacus | encyclopedia = Merriam-Webster's Collegiate Dictionary | year = 2003 | edition = 11th | isbn = 978-0-87779-809-5 | url = https://archive.org/details/merriamwebstersc00merr_6 }}
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* {{cite web |last=Murray |first=Geoffrey |url=http://www.csmonitor.com/1982/0720/072033.html |title=Ancient calculator is a hit with Japan's newest generation |website=The Christian Science Monitor |publisher=CSMonitor.com |date=July 20, 1982 |access-date=July 31, 2014 |archive-date=December 2, 2013 |archive-url=https://web.archive.org/web/20131202224138/http://www.csmonitor.com/1982/0720/072033.html |url-status=live |df=mdy }}
* {{cite encyclopedia | editor1-last = Onions | editor1-first = C. T. | editor2-last = Friedrichsen | editor2-first = G. W. S. | editor3-last = Burchfield | editor3-first = R. W. | title = abacus | encyclopedia = The Oxford Dictionary of English Etymology | publisher = Oxford at the Clarendon Press | location = Oxford, UK | year = 1967 }}
* {{cite book|title=Assistive Technology for Students who are Blind Or Visually Impaired: A Guide to Assessment|first1=Ike|last1=Presley|first2=Frances Mary|last2=D'Andrea|publisher=American Foundation for the Blind|year=2009|isbn=978-0-89128-890-9|page=61|url=https://books.google.com/books?id=ooYPHSv7hEoC&pg=PA61}}
* {{cite book | last = Pullan | first = J. M. | year = 1968 | title = The History of the Abacus | publisher = Frederick A. Praeger, Inc., Publishers | location = New York, NY | isbn = 978-0-09-089410-9 | lccn = 72075113 }}
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{{Refend}}

== Further reading ==
{{Refbegin}}
* {{cite web |last=Fernandes |first=Luis |url=http://www.ee.ryerson.ca/~elf/abacus/history.html |title=The Abacus: A Brief History |year=2013 |work=ee.ryerson.ca |access-date=July 31, 2014 |archive-date=July 2, 2014 |archive-url=https://web.archive.org/web/20140702214749/http://www.ee.ryerson.ca/~elf/abacus/history.html |url-status=live |df=mdy }}
* {{Cite book | last = Menninger | first = Karl W. | year = 1969 | title = Number Words and Number Symbols: A Cultural History of Numbers | publisher = MIT Press | isbn = 978-0-262-13040-0}}
* {{Cite book | last = Kojima | first = Takashi | year = 1954 | title = The Japanese Abacus: its Use and Theory | publisher = Charles E. Tuttle Co. | location = Tokyo | isbn=978-0-8048-0278-9}}
* {{Cite book | last = Kojima | first = Takashi | year = 1963 | title = Advanced Abacus: Japanese Theory and Practice | publisher = Charles E. Tuttle Co. | location = Tokyo | isbn=978-0-8048-0003-7}}
* {{Cite book |last=Stephenson |first=Stephen Kent |url=http://www.ieeeghn.org/wiki/index.php/Ancient_Computers |title=Ancient Computers |date=July 7, 2010 | publisher = IEEE Global History Network |access-date=2011-07-02|arxiv=1206.4349 |bibcode=2012arXiv1206.4349S }}
* {{Cite book | last = Stephenson | first = Stephen Kent | year = 2013 | title = Ancient Computers, Part I - Rediscovery| publisher = CreateSpace Independent Publishing Platform |edition = 2nd | isbn = 978-1-4909-6437-9}}
{{Refend}}

==External links==
{{wiktionary}}
{{Commons}}
* {{Wikisource-inline|list=
** "[[s:A Dictionary of Greek and Roman Antiquities/Abacus|Abacus]]", from ''[[s:A Dictionary of Greek and Roman Antiquities|A Dictionary of Greek and Roman Antiquities]]'', 3rd ed., 1890.
}}
**{{cite EB9 |wstitle = Abacus |volume= I | page=4 |short=1}}
**{{Cite EB1911|wstitle=Abacus |short=x |noicon=x}}

===Tutorials===
<!-- in alphabetical order by author -->
* {{Citation | url = http://totton.idirect.com/abacus/ | title = Abacus: Mystery of the Bead - an Abacus Manual | first = Totton & Gary Flom | last = Heffelfinger}}
* [https://web.archive.org/web/20110728141638/http://www.minmm.com/minc/show_classes.php?id=273 Min Multimedia]
* {{Citation |url=https://www.youtube.com/watch?v=4Qp5JcceUEM&list=PL545ABCC6BA8D6F44 |title=How to use a Counting Board Abacus |first=Stephen Kent |last=Stephenson |year=2009}}

===History===
* {{Citation | url = https://kartsci.org/kocomu/computer-history/history-abacus-ancient-computing/ | title = History of Abacus and Ancient Computing | first = Vladimir| last = Esaulov |  year = 2019}}
* {{Citation | url =https://www.ecb.torontomu.ca/~elf/abacus/history.html| title = The Abacus: a Brief History
}}

===Curiosities===
* {{Citation | url = http://demonstrations.wolfram.com/Abacus/ | title = Abacus | first = Michael | last = Schreiber | publisher = The [[Wolfram Demonstrations Project]] | year = 2007}}
* [http://www.cut-the-knot.org/blue/Abacus.shtml Abacus in Various Number Systems] at [[cut-the-knot]]
* [https://web.archive.org/web/20041009110126/http://www.tux.org/~bagleyd/abacus.html Java applet of Chinese, Japanese and Russian abaci]
* [http://www.research.ibm.com/atomic/nano/roomtemp.html An atomic-scale abacus]
* [http://tinas-sliderules.me.uk/Slide%20Rules/Abaci.html Examples of Abaci]
* [https://web.archive.org/web/20080907180002/http://www.tux.org/~bagleyd/java/AbacusAppMA.html Aztex Abacus]
* [https://www.indianabacus.com/ Indian Abacus]
* [https://www.mathcruise.com/course/abacus/ Abacus Course]

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