Q: WHAT YEAR DID ABIJAM'S REIGN END IN JUDAH?
A: IT DEPENDS WHAT CALENDAR YOU ARE USING!
On the Gregorian calendar (the one you might have on your wall) the year was 899 BC.
On the Hebrew calendar, sometimes called the biblical calendar, the year was 3148 AM.
1 Kings 15:1-2 – Now in the eighteenth year of king Jeroboam the son of Nebat reigned Abijam over Judah. Three years reigned he in Jerusalem. And his mother's name was Maachah, the daughter of Abishalom.
1 Kings 15:9-10 New King James Version (NKJV)
Asa Reigns in Judah
9 In the twentieth year of Jeroboam king of Israel, Asa became king over Judah. 10 And he reigned forty-one years in Jerusalem. His grandmother’s name was Maachah the granddaughter of Abishalom.