'Eighteen' in the Bible

Jehoiachin was eighteen years old when he became king, he was ruling in Jerusalem for three months, and his mother's name was Nehushta, the daughter of Elnathan of Jerusalem.

One of the pillars was eighteen cubits high, with a crown of brass on it; the crown was three cubits high, circled with a network and apples all of brass; and the second pillar had the same.