What does 2 Chronicles 36:11 mean?

2 Chronicles 36:11 KJV
Zedekiah [was] one and twenty years old when he began to reign, and reigned eleven years in Jerusalem.

2 Chronicles 36:11 MKJV
Zedekiah [was] twenty-one years old when he began to reign, and he reigned eleven years in Jerusalem.

2 Chronicles 36:11 NKJV
Zedekiah [was] twenty-one years old when he became king, and he reigned eleven years in Jerusalem.

2 Chronicles 36:11 KJV 2000
Zedekiah was one and twenty years old when he began to reign, and reigned eleven years in Jerusalem.

Interlinear KJV

Zedekiah /Tsidqiyah/ was one /’echad/ and twenty /`esriym/ years /shaneh (in pl. only),/ old /ben/ when he began to reign, /malak/ and reigned /malak/ eleven /’echad/ /`asar/ years /shaneh (in pl. only),/ in Jerusalem. /Y@ruwshalaim/

Jamieson Fausset-Brown

2Ch 36:11-21. ZEDEKIAH’S REIGN. 11. Zedekiah–Nebuchadnezzar appointed him. His name, originally Mattaniah, was, according to the custom of Oriental conquerors, changed into Zedekiah. Though the son of Josiah (1Ch 3:15; Jer 1:2,3; 37:1), he is called the brother of Jehoiachin (2Ch 36:10), that is, according to the latitude of Hebrew style in words expressing affinity, his relative or kinsman (see 2Ki 24:18; 25:1-21).