## 777, 365, and 21

Posted: March 26, 2017 in Mathematics

The number “689” has been the laughingstock of the HK chief executive for the past 4 years. “689” basically means 冇柒用, so in response, this year’s chief executive will receive “777” votes just to emphasis that she is very 好有柒用. It’s not one 7 or two 7s, but three 7s in a row, how nice!

Actually 777 is quite an interesting number. In gambling, it is a lucky number to most people because “777” is a jackpot number. In computer science, “777” means you have been granted read, write, and executable permission on a file (in UNIX or UNIX-like operating system such as Linux, BSD, Mac OSX, etc). To most HKers, 777, 365, and 21 mean the number of vote of today’s HK chief executive election. To me, I have another interpretation.

$777 = 7 \cdot 111 = 7 \cdot 3 \cdot 37$

$365 = 5 \cdot 73$

$21 =3 \cdot 7$

$\therefore 777 \cdot 365 \cdot 21 = 7 \cdot 3 \cdot 37 \cdot 5 \cdot 73 \cdot 3 \cdot 7$

Math is beautiful, isn’t it?

###### Remarks

The joke has made into wikipedia LOL