system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5: Why do dancers start with a “5, 6, 7, 8” count?

Why is this and what’s the point? Why not just start at 1, 2, 3, 4?

P.S. I’m a ballerina

Update: Thank you so much everyone for participating in this post. Your replies have my wheels turning and I feel like I’ve learned alot. Everything from music theory, to dance technique, and more. Now time for me to enter stage left for my big performance in the Nutcracker Ballet. Wish me luck, or shall I say….break a leg.
gpt
Music tends to be grouped into sets of beats--often 3 or 4 beats to a set (known as a measure).

That winds up being too few for dancing "phrases," so dancers tend to group a couple of measures together.  They'll often count 1, 2, 3, 4, 5, 6, 7, 8, 1, 2, 3..., looping back to 1 every time they get to 8.

The first step of the dance will be on a count of "1," and the four numbers that precede 1 are 5, 6, 7, and 8.