'Thirty' in the Bible

Furthermore, from the day King Artaxerxes appointed me to be their governor in the land of Judah—from the twentieth year until his thirty-second year, 12 years—I and my associates never ate from the food allotted to the governor.

The children of Senaah, three thousand nine hundred and thirty.

The porters: the children of Shallum, the children of Ater, the children of Talmon, the children of Akkub, the children of Hatita, the children of Shobai, an hundred thirty and eight.

Beside their manservants and their maidservants, of whom there were seven thousand three hundred thirty and seven: and they had two hundred forty and five singing men and singing women.

Their horses, seven hundred thirty and six: their mules, two hundred forty and five:

Their camels, four hundred thirty and five: six thousand seven hundred and twenty asses.

And some of the chief of the fathers gave unto the work. The Tirshatha gave to the treasure a thousand drams of gold, fifty basons, five hundred and thirty priests' garments.

While all this was happening, I was not in Jerusalem, because I had returned to King Artaxerxes of Babylon in the thirty-second year of his reign. It was only later that I asked the king for a leave of absence