DECIMAL NOTATION • E-FREE TRANSLATION.COM • Definition of Decimal notation

... this ['s][u]nya as a symbol was not used before about 500 A.D., although some writers have placed it earlier.[147] Since [A]ryabha[t.]a gives our common method of extracting roots, it would seem that he may have known a decimal notation,[148] although he did not use the characters from which our numerals are derived.[149] Moreover, he frequently speaks of the {44} void.[150] If he refers to a symbol this would put the zero as far back as 500 A.D., but of course he may have referred ...

— The Hindu-Arabic Numerals • David Eugene Smith