105
51 is divisible by 3!
(sh.itjust.works)
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
this post was submitted on 23 Sep 2024
105 points (95.7% liked)
Unexpected Factorial
179 readers
2 users here now
When you use an exclamation mark with a number, you’re actually implying it’s not a normal number any more. It’s a factorial!
Ok, so how does this work?
5!=1×2×3×4×5=120
6!=720
These numbers get really large. For example:
15!≈1.3×10^12
So, next time you see a headline with 2000! in it, you’ll know what to expect.
There are also double factorials (n!!) and iterated factorials (n!)!, and they aren’t the same thing. Just add more exclamation marks and you get multifactorial. Check wikipedia to see how spicy it gets.
founded 2 years ago
MODERATORS
π=3
Source: Mahajan, S. (2014). The art of insight in science and engineering: Mastering complexity. The MIT Press. p. 18.
That page is also a goldmine for of numbers you can use for back of the envelope maths or trolling professionals of various kinds. Are you working with chemists? N_A=6 * 10^23 mol^-1 What about physicists then? c=3 * 10^8 m/s.