Well, it happened again. A "special" date popped up that caught people's attention, so I have emails in my inbox letting me know about it (which I love, by the way - keep 'em coming!).What strikes me as interesting is that so many people "hate" math, but yet so many people are intrigued by properties of numbers - or have lucky numbers - in some way have some affinity for number or pattern. I can't help but wonder if something we do in the schools, forcing some sort of performance anxiety or something, is what turns people off to math and causes them to hate it. It's been my experience that people actually like number puzzles and patterns, even if they claim to hate math. If this wasn't the case I wouldn't get so many emails about things like this with the subject line, "Check this out! Really cool!"
Today is "special" because it is (to write it one way) 9/9/9.
If you're interested in more about this day and the number 9, click on this link. Different cultures have different meanings associated with different numbers. In many countries 7 is considered a lucky number, and 13 is considered unlucky (to the point where some tall buildings have a 12th floor and a 14th floor but no 13th floor in between). In China 8 is considered particularly lucky because the word "eight" in Chinese sounds like the word for wealth. Remember last year, the Olympic Games were opened in China at 8pm on 8/8/8.
What follows is a little math paradox for you on this "special" day.
Numbers have a variety of properties assoctiated with them. There are all sorts of numbers. They can be odd, even, prime, square, triangular; there are even perfect numbers, amicable numbers, narcissistic numbers and schizophrenic numbers and many, many other types.
For example, six is a perfect number because all the whole numbers below it that divide into it also add up to it: 1+2+3=6. Six is the smallest perfect number, so it is an "interesting number" (or so some would say :-).
Here's the paradox. If we try to separate numbers into those that are "interesting" and those that are "un-interesting," we find that all numbers are interesting. If we begin at 1 and work our way up, noting the interesting properties of each number, when we came across the first one that was "un-interesting," it would be interesting BECAUSE it was the first un-interesting number - and so on. So, all numbers are interesting!