Can someone explain this trend I see a lot that I have no idea what it is. Obviously a 6 year old can tell the math doesn't make sense. So why do this? So many do this and it is so confusing.

The answer is porn. It is always porn.

Birth years? And yes I know, but there must be a story.

Because it's confusing you stop and pause and watch the video to try to figure it out, which is engagement which shows it to more people