Definite article before number

Question

I know that "los dos sabemos" (ambos sabemos) mean "we both know". Similarly, "los tres sabemos" - "we three know".

But when definite article is used before numbers in other cases? As for me, more frequently I encounter only "definite article + noun" or "number + noun (and no definite article)". But below are different examples, for which I would ask you to explain why definite article is used:

1) "los 380 flying fortress" - this was referring to 380 Flying Fortress planes (from movie about World War 2).

2) From article regarding 9/11 in Wiki, in the first paragraph (https://es.wikipedia.org/wiki/Atentados_del_11_de_septiembre_de_2001): "«11S», fueron una serie de cuatro atentados terroristas suicidas cometidos la mañana del martes 11 de septiembre de 2001 en los Estados Unidos por la red yihadista Al Qaeda que mediante el secuestro de aviones comerciales para ser impactados contra diversos objetivos causaron la muerte de 3016 personas, incluidos LOS diecinueve terroristas."

Here, why "los" is used for "19 terroristas", but not used before "3016 personas"? My guess - in case of terrorists it is used to state that all 19 of them died (similar to "los dos sabemos" example), but I would use word "todos" before "los 19" to emphasize this.

Answer 1

In the first case, as you guessed, los 380 Flying Fortress is short for los 380 aviones del tipo Flying Fortress. That is, the three hundred and eighty planes of that type that have been (presumably) previously mentioned somewhere. This isn't a special usage of the definite article with numbers; the phrase would work as well without any number or with an adjective like inmensos or innumerables or whatever. The article just specifies that you're talking about those 380 planes and not others.

In the second example, you don't use the definite article with the victims because the referrent is not definite in that context. This works the same as in English. If you say la muerte de 3016 personas then it means 3016 people died. If you said (in this sentence) la muerte de las 3016 personas then one would be left wondering who these particular 3016 people are, because no specific number of victims has been mentioned before.

As for the definite article used in los 19 terroristas, I would say it's a mistake, if not a terrible one. If the text began by saying that the attacks were conducted by 19 terrorists, and then talked about the victims as in the excerpt you gave, then the definite article would be OK (although the number wouldn't need to be repeated). As you say, as it stands, it sounds like it's trying to emphasize that all of them died. Note that in Spanish it's not idiomatic to say things like todos los diecinueve terroristas (copying the English structure). One way to salvage this text would be to say ...incluidos los 19 terroristas involucrados en los diferentes atentados....