The zero, and who has one
The floor's dividing lineZero is the only thing on this floor that is genuinely difficult. A system that sums its signs never needs one: nothing is missing from MMXXVI, because nothing is positional. A system whose digits take meaning from their column cannot manage without a way to say this column is empty — and inventing a sign for nothing is a conceptual step, not a notational convenience.
It was taken at least twice, by people who never met: in South Asia, and in Mesoamerica.
Babylon shows the cost of getting halfway. It had place value from around 2000 BCE and no zero for well over a millennium, so a scribe wrote the digits and the reader supplied the magnitude from context. The oldest securely dated zero on this floor is neither Indian nor Maya: it is a dot on a Khmer inscription of 683 CE. See Khmer, Maya and Babylonian.
Additive Hall
5 systemsSigns are summed. No columns, so no empty column to mark — and no zero.
Positional Hall
13 systemsA digit's value depends on where it sits. Needs a zero to hold an empty place.
The Naming Hall
2 systemsDigit times named power, written the way the number is said.
Digits in use
All 20, one line each| Digits | System | Structure | Base | Zero | Status |
|---|---|---|---|---|---|
| Devanagari numerals | positional | 10 | yes | living | |
| Arabic-Indic numerals | positional | 10 | yes | living | |
| Roman numerals | additive | 10 | — | living | |
| Babylonian numerals | positional | 60 | — | historic | |
| Maya numerals | positional | 20 | yes | historic | |
| Egyptian numerals | additive | 10 | — | historic | |
| Greek numerals | additive | 10 | — | living | |
| Cyrillic numerals | additive | 10 | — | historic | |
| Ethiopic numerals | additive | 10 | — | living | |
| Chinese numerals | multiplicative | 10 | yes | living | |
| Japanese numerals | multiplicative | 10 | yes | living | |
| Tamil numerals | positional | 10 | yes | living | |
| Bengali numerals | positional | 10 | yes | living | |
| Telugu numerals | positional | 10 | yes | living | |
| Kannada numerals | positional | 10 | yes | living | |
| Malayalam numerals | positional | 10 | yes | living | |
| Thai numerals | positional | 10 | yes | living | |
| Khmer numerals | positional | 10 | yes | living | |
| Burmese numerals | positional | 10 | yes | living | |
| Tibetan numerals | positional | 10 | yes | living |
This floor holds numeral systems — sets of digits that mean by sequence and position. Standalone quantity marks that mean on their own, including the currency signs and the number sign, are read at symbolic.institute.