Now in the eighteenth year of King Jeroboam the son of Nebat
reigned Abijam over Judah.
] That is, began to reign; and by this it appears that Rehoboam was in the eighteenth year of his reign when he died, for he and Jeroboam began their reign at the same time.
The Brenton translation of the Septuagint is in the public domain.