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?