Joas [was] seven years old when he began to reign.
KJV
2 Kings 12:1
In the seventh year of Jehu Jehoash began to reign; and forty years reigned he in Jerusalem. And his mother’s name was Zibiah of Beer–sheba.
Parallel Translations
Joas began to reign in the seventh year of Ju, and he reigned forty years in Jerusalem: and his mother's name [was] Sabia of Bersabee.
Jehoash began to reign in the seventh year of Jehu, and he reigned forty years in Jerusalem. His mother’s name was Zibiah of Beersheba.
Cross References
Cross references via openbible.info (CC-BY)