He numbered them - This was done to see who was absent (compare Judges 21:9).
Bezek has been conjectured to be the name of a district rather than of a town. Two villages retained the name in the time of Eusebius 17 miles from Nablous, on the way to Beth-shean.
The children of Israel and the men of Judah - This looks like the language of later times, times perhaps subsequent to the establishment of the two kingdoms of Israel and Judah. Israel here (including Benjamin) is as ten to one compared with Judah. This is about the true proportion.