ネイティブと話していて”Let’s take five.”と言うのを聞いたことありませんか？
take five の意味は？
That's right! When someone says, "Let's take five," it means "Let's take a five-minute break." The phrase is a shortened version of this sentence.
But be careful, because if you omit "Let's" and just say, "Take five," it will sound like a command. This will only be appropriate if you're the leader of the group you're talking to.
Yes, native English speakers often use this phrase. Alternatively, you could say, "Let's take 10," if you want to take a 10-minute break. I haven't heard many Japanese students use this phrase. Maybe that’s because usually it is the teacher who says this phrase!