It's 9-9-9 today! It's the ninth day of the ninth month of the ninth year of the decade....I just wasted a lot of time well spent watching the old Square One videos on Youtube. Here's another one of my favourites:
Why is it so special? The number 9 has different significances in different countries, and is important for math theory as well. As far as the calendar goes:
"...it also represents the last set of repeating, single-digit dates that we'll see for almost a century (until January 1, 2101), or a millennium (mark your calendars for January 1, 3001), depending on how you want to count it."
Check out this great article on the history and significance of the number 9. There's another article here also. Thanks to the edmontonian for the link!
Whenever I think of the number 9, I get transported back to the eighties. One of my favourite TV shows was 'Square One', a fun math show on PBS. I often used the tricks I learned from this show as a kid in my classroom. There's a neat 9 times table finger trick that can be done by putting down certain fingers and counting how many are left on each side, which the kids loved because it was "like cheating". And of course there's the trick of adding the digits from a 9 times table fact. Check that out here, from one of my favourite Square One videos (seriously I still know all the words to this one!):
And there's a bunch of Mathnet videos on there too. Ah nostalgia, ain't it great!