2 Kings 11:21

"Seven years old was Jehoash when he began to reign."

Cross References (ranked by relevance)

And the seventh year Jehoiada sent and fetched the rulers over hundreds, with the captains and the guard, and brought them to him into the house of the LORD, and made a covenant with them, and took an oath of them in the house of the LORD, and shewed them the king’s son.

2 Kings 22:1

Josiah was eight years old when he began to reign, and he reigned thirty and one years in Jerusalem. And his mother’s name was Jedidah, the daughter of Adaiah of Boscath.