9th September: The number nine

It's the ninth day of the ninth month - so what better time to present you with ten facts about the number nine.

1. A group of nine of anything is called an ennead. A polygon with nine sides is called a nonagon or enneagon.
2. In some European languages, French, German and Spanish, for example, the word for nine is the same as the word for "new". Nine being the final single digit number in base 10, when you reach nine, you are about to make a new start.
3. Nine is the atomic number of Fluorine.
4. Nine is considered a good number in China because the Chinese word for it is similar to the word for "long-lasting". It's a different story in Japan, though, as the Japanese word for nine sounds similar to the Japanese word for pain.
5. To work out if a number is divisible by nine, add up the digits, then add the digits of the resulting number until you're left with a single digit. If that digit is nine, then the number is divisible by nine.
6. In literature and mythology, there are nine rings of power in Tolkien's Lord of the Rings and nine members of the Fellowship of the Ring; There are nine circles of Hell in Dante's Divine Comedy (The ninth circle is for traitors); in Game of Thrones, Westeros has nine regions (the Crownlands, the North, the Riverlands, the Westerlands, the Reach, the Stormlands, the Vale of Arryn, the Iron Islands and Dorne); There are nine muses in Greek mythology; and in Norse mythology, Odin hung himself on an Ash tree for nine days to learn the runes.
7. The phrase "on cloud nine" came into use in the 1950s from a term used by the US Weather Bureau. Cloud Nine is cumulo-nimbus cloud at a height of 10 km, high even for clouds. Hence if you are on cloud nine, you are euphoric, or high.
8. In sport, the number nine is: the centre forward in soccer, the right fielder in Baseball, the hooker in rugby league, the scrum half in rugby union. The game of ninepin Bowling was banned in some US states because it was associated with gambling. They got around it by adding an extra pin and calling it ten pin bowling.
9. A Cat is said to have nine lives, due to a belief that a witch could take the form of a cat nine times.
10. The 9 of diamonds is sometimes called the Curse of Scotland. The most common explanation for this is that Sir John Dalrymple, the Earl of Stair, used this card to authorise the Glen Coe Massacre in 1692.