Numeroan

Numeroan is a constructed numeral system used in the fictional world of Numeria. It serves as both a counting method and a written notation for numbers, and it has been described in conlang and speculative-fiction literature as part of the world’s mathematical culture. The system is base-12 (duodecimal) and relies on a fixed set of twelve digit symbols.

Digits represent zero through eleven, with ten and eleven given distinct glyphs beyond the ten digits used for zero to nine. Numbers of any size are formed by positional notation, using powers of twelve rather than powers of ten. In practice, large numbers are written and read by grouping digits in twelfths, with separators similar to the decimal comma but placed to indicate 12^1 groups, 12^2 groups, and so on.

As with any numeration system, common terms and cultural conventions influence usage. The number ten is written as X, eleven as E, while the digits zero through nine are shared with the decimal system. For instance, decimal 125 equals 10×12 + 5, which in Numeroan is written as X5. Decimal 144 equals 1×12^2, which is written as 100 in the Numeroan system.

Historically, Numeroan was developed as part of a broader project to model Numerian mathematics and education. It has been used in fiction to express technical content, in translated texts within the world, and in fan-created grammars and encodings of Numerian culture.