Arabic numerals milestone in the development of mathematics. One may distinguish between this positional "system", which is identical throughout the family, and the precise glyphs used to write the numerals, which varied regionally. The first universally accepted inscription containing the use of the 0 glyph in India is first recorded in the 9th century, in an inscription at Gwalior in Central India dated to 870. Numerous Indian documents on copper plates exist, with the same symbol for zero in them, dated back as far as the 6th century AD, but their dates are uncertain. Inscriptions in Indonesia and Cambodia dating to AD
Numerals in Unicode three Unicode characters semantically represent mathematical constants: , the , and . Other mathematical constants can be represented using characters that have multiple semantic uses. For example, although Unicode includes a character for "natural exponent" ℯ (U+212F) its UCS canonical name derives from its glyph: ; and the mathematical constant π, 3.141592.., is represented by . The Western Arabic numerals also appear among the compatibility characters as rich text variant forms including bold, double-struck, monospace, sans-serif and sans-serif bold. and fullwidth variants for legacy vertical text support. Rich text parenthesized, circled and other variants are also included in the blocks: