Following the adoption of Greek Hellenistic alphabetic numeration practice, Hebrew letters started being used to denote numbers in the late 2nd century BC, and performed this arithmetic function for about a thousand years. Nowadays alphanumeric notation is used only in specific contexts, e.g. denoting dates in the Hebrew calendar, denoting grades of school in Israel, other listings (e.g. שלב א׳, שלב ב׳ – "phase a, phase b"), commonly in Kabbalah (Jewish mysticism) in a practice known as gematria, and often in religious contexts.