'Eighteen' in the Bible

A son of eighteen years is Jehoiachin in his reigning, and three months he hath reigned in Jerusalem, and the name of his mother is Nehushta, daughter of Elnathan of Jerusalem,

eighteen cubits is the height of the one pillar, and the chapiter on it is of brass, and the height of the chapiter is three cubits, and the net and the pomegranates are on the chapiter round about -- the whole is of brass; and like these hath the second pillar, with the net.