system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: 196884 = 196883 + 1

Apparently, there is a much deeper mathematical significance to what seems to be a simple random (yet sound) equation. I've seen it referenced as "Monstrous Moonshine" and has something to do with dimensionalities, but everywhere I look gives increasingly cryptic answers.
gpt
196884 is the first number which appears when you try to write down a very special example of something called a modular function (not really important to the story what this is).

1 and 196883 appear as the first two numbers which appear when you write down certain properties of a very special example of something called a group.

The fact that you could add the latter two to get the first, even though they appear completely random on their own, lead to mathematicians trying to find a connection between modular functions and groups, which come from completely different fields of mathematics.

Say you ask your friend Larry his favorite number and he says 196884. Say you go on vacation to Morocco the next week and meet a nice old lady and ask her favorite numbers and she says 1 and 196883. You'd be freaked out right? Mathematicians were freaked out.