Tally marks

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Counting using tally marks at Hanakapiai Beach.

Tally marks, also called 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[edit]

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.

Writing systems[edit]

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[edit]

References[edit]

  1. ^ Hsieh, Hui-Kuang (1981) "Chinese tally mark", The American Statistician, 35 (3), p. 174, doi:10.2307/2683999
  2. ^ Schenck, Carl A. (1898) Forest mensuration. The University Press. (Note: The linked reference appears to actually be "Bulletin of the Ohio Agricultural Experiment Station", Number 302, August 1916)