This is the 4567th most frequent Korean word.
가량은
Approximately; about.
가량은 is used to estimate the time duration in this sentence.
그는 일을 하는데 두 시간 가량은 걸릴 것이다.
It will probably take him about two hours to finish the work.
가량은 indicates an approximation of the number of pages here.
이 책은 300쪽 가량은 되는 것 같아.
This book seems to be about 300 pages.
가량은 is employed to express an estimated quantity of students in this context.