足りません - can it also mean 'missing'?

Question

I'm putting together an Anki deck based on the Tatoeba corpus, and I'm uncertain about the translation provided for one of the sentences. The sentence "スミス先生、生徒が二人足りません。" is translated as "There are two students missing, Mr. Smith." My concern is with the use of 足りません here. Is this the most natural way to express this sentiment?

I'm familiar with 足りません in its meanings of 'to be insufficient' or 'to not be worthy', and it seems to a poor student like myself that the sentence should be "Two students are not enough [for the implied task], Mr. Smith." If 足りません isn't appropriate for the given translation, would 抜ける or 無くなる be better choices?

Answer 1

I'm pretty sure that in this case, a more "transparent" translation would be "Mr. Smith, we're two students short." To me, the implication seems to be that 足りません means "insufficient" in the sense that whatever number of students they have is two short of being a full class, thus it is "insufficient" or "not enough" to call it a full class. Thus 生徒二人 in this case is an adverb. If we were using your interpretation of "two students are not enough," the sentence would be something like: "スミス先生、二人の生徒では足りません" or something like that.