I once met a guy who said he could count anything instantly. I had to test his claim. "This is my ranch, and over there's my cattle. How many are there?"
He looked over, paused for the briefest moment, and then said, "I see 742 cows."
Astonished, I exclaimed, "That's exactly right! Mind sharing your secret?"
He leaned in a bit and proudly explained. "It's simple, really. I count the number of legs and divide by four."
It's a well-known "joke", and it clearly plays off the idea of this article wherein calculating 52! is, genuinely, done by calculating 54! then dividing by a correction factor.
He looked over, paused for the briefest moment, and then said, "I see 742 cows."
Astonished, I exclaimed, "That's exactly right! Mind sharing your secret?"
He leaned in a bit and proudly explained. "It's simple, really. I count the number of legs and divide by four."