Matthew reports: “when will these things happen and what will be the sign of your presence and of the end of the system of things”.
You’re using a Jehovah’s Witness bible, aren’t you?
That’s not a translation of Mt 24:3 that’s particularly true to the original Greek. In the original, Mt 24:3 talks about the “συντελείας τοῦ αἰῶνος” (that is, “synteleias tou aionos”). You can see in “synteleias” the root “telos”, which means “end” or “goal” or “completion”, and “aionos” is the word which gives rise to the English word “eon” (meaning “era” or “age”).
So, it’s not really “the end of the system of things”; it’s “the completion of [this] era” – or, as it were, “the end of the world.”
(Edited to add
Also, it’s not a “sign of your presence” in any of the translations I’ve seen, IIRC. The word for “presence” in the text is
παρουσίας (“parousias”). We continue to use this word in English: the parousia is the
second coming of Jesus. So, the use of the word here is more than mere ‘presence’; it’s more like “arrival” or “coming”.
The questions to Jesus in Mark and Luke are slightly different from Matthew who is more precise.
Not sure I’d say “more precise”. Rather, Matthew’s Gospel simply includes an additional question, regarding Jesus’ second coming. Now, we could discuss whether we think that the Gospel of Mark came first (and therefore, Matthew added extra detail), or that the Gospel of Matthew came first (and therefore, Mark omitted this detail), but it is accepted that Luke assembled his Gospel after both Matthew and Mark. Therefore, it seems that he followed Mark’s take on it in this verse – that is, omitting the question of the second coming. It’s an interesting question to consider: what should we make of Luke’s editorial decision?