Tally marks

Tally marks, or hash marks, are a unary numeral system. They are a form of numeral used for counting. They are most useful in counting or tallying ongoing results, such as the score in a game or sport, as no intermediate results need to be erased or discarded. However, because of the length of large numbers, tallies are not commonly used for static text. Notched sticks, known as tally sticks, were also historically used for this purpose.

Clustering

Various ways to cluster the number 8. The first or fifth mark in each group may be written at an angle to the others for easier distinction. In the fourth example, the fifth stroke "closes out" a group of five, forming a "herringbone". In the fifth row (used in Brazil, France, and the United States) the fifth mark crosses diagonally, forming a "five-bar gate".

Tally marks are typically clustered in groups of five for legibility. The cluster size 5 has the advantages of (a) easy conversion into decimal for higher arithmetic operations and (b) avoiding error, as humans can far more easily correctly identify a cluster of 5 than one of 10.

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  Tally marks used in most of Europe, Turkey, Zimbabwe, Australia, New Zealand and North America.
  In some variants, the diagonal/horizontal slash is used on its own when five or more units are added at once. Two groups of five lines (i.e. ten tally marks) are sometimes circled.^{[citation needed]}

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  Cultures using Chinese characters tally by forming the character 正, which consists of five strokes.

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  Tally marks used in France, Spain, South America (Argentina, Brazil, Chile, Venezuela and Uruguay, among others) and French-speaking Africa. In Spanish countries, these are most commonly used for registering scores in card games, like Truco

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  In the dot and line (or dot-dash) tally, dots represent counts from 1 to 4, lines 5 to 8, and diagonal lines 9 and 10. This method is commonly used in forestry and related fields.

Writing systems

Brahmi numerals (lower row) in India in the 1st century CE

Roman numerals, the Chinese numerals 一 二 三, and rod numerals were derived from tally marks, as possibly was the ogham script.^{[citation needed]}

See also

• Finger-counting
• Hangman (game)
• List of international common standards
• Prehistoric numerals
• Quipu