Undecimal

Undecimal (also known as unodecimal, undenary, and the base 11 numeral system) is a positional numeral system that uses eleven as its base. While no known society counts by elevens, two are purported to have done so: the Māori (one of the two Polynesian peoples of New Zealand) and the Pañgwa (a Bantu-speaking people of Tanzania). The idea of counting by elevens remains of interest for its relation to a traditional method of tally-counting practiced in Polynesia. During the French Revolution, undecimal was briefly considered as a possible basis for the reformed system of measurement. Undecimal numerals have applications in computer science, technology, and the International Standard Book Number system. They also occasionally feature in works of popular fiction. In undecimal, a capital letter (often A, the symbol for 10 in hexadecimal; T, the first letter of the English word "ten"; or X, the Roman numeral 10) or the digit ↊ (called "dek") is typically used as a transdecimal symbol to represent the number 10.