10!=10\*9\*8\*7\*6\*5\*4\*3\*2\*1

https://feddit.org/post/26532917

It took me way too long to understand the joke, I may be fucking dumb
I still don’t get it, so… you could be worse.

10! means ten factorial. So 10 * 9 * 8 * 7 * 6 * 5 * 4 * 3 * 2 * 1.

It’s a common math joke.