They seemed unsure about the status of zero as a number.
In a tablet unearthed at Kish (dating from about 700 BC), the scribe Bêl-bân-aplu wrote his zeros with three hooks, rather than two slanted wedges.
The Babylonian placeholder was not a true zero because it was not used alone. Thus numbers like 2 and 120 (2×60), 3 and 180 (3×60), 4 and 240 (4×60), looked the same because the larger numbers lacked a final sexagesimal placeholder. The back of Epi-Olmec stela C from Tres Zapotes, the second oldest Long Count date discovered.
Another zero was used in tables alongside Roman numerals by 525 (first known use by Dionysius Exiguus), but as a word, nulla meaning "nothing", not as a symbol.
When division produced zero as a remainder, nihil, also meaning "nothing", was used.
Ptolemy's zero was used within a sexagesimal numeral system otherwise using alphabetic Greek numerals.
Because it was used alone, not just as a placeholder, this Hellenistic zero was perhaps the earliest documented use of a numeral representing zero in the Old World.
The number 0 fulfills a central role in mathematics as the additive identity of the integers, real numbers, and many other algebraic structures.
As a digit, 0 is used as a placeholder in place value systems.
Sometimes the words nought, naught and aught are used.