This is the 792nd most frequent Korean word.
몇
"몇" means "how many" or "a few" in English.
몇 is used here to inquire about a quantity of people (students).
몇 명의 학생이 교실에 있습니까?
How many students are in the classroom?
몇 is used to ask for a specific number regarding age.
그는 몇 살입니까?
How old is he?
몇 is used to indicate a small or uncertain number of things (questions).