エスキモー・アレウト語族
The Iñupiaq language has a base-20 numeral system, as do all the Eskimo–Aleut languages of Alaska and Canada. The familiar Arabic numerals, which were designed for a base-10 system, are inadequate for Iñupiaq and other Inuit languages. To remedy this problem, students in Kaktovik, Alaska, invented a base-20 numeral notation in 1994, which has spread among the Alaskan Iñupiat and has been considered for use in Canada.