Tally marks
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Tally marks, also called hash marks, are used as a basic numeral system for counting; they can be thought of as a unary numeral system.
A "five-barred gate" on a chalkboard
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.
Ishango bone
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The Ishango bone, discovered at the "Fisherman Settlement" of Ishango in the Democratic Republic of the Congo, is a bone tool and possible mathematical device that dates to the Upper Paleolithic era.
Tally marks
…30,000 years ago, the bone is marked with 55 marks which may be tally marks. The head of an ivory Venus figurine was excavated close to the bone. The Ishango bone, found in the Ishango region of the present-day Democratic Republic of Congo, is dated to over 20,000 years old. Upon discovery, it was thought to…
The Ishango bone on exhibition at the Royal Belgian Institute of Natural Sciences