Iowa hung this post from the tumblr of “thepowerofmoonlight” on The Bulletin Board the Number People Use (the one outside the Math and Statistics bay in the SciTech Library) and posted it on the general Noakes Library tumblr, too. After all, she says, everybody uses numbers. Don’t forget to tip your server!
“Learnt an interesting thing today on this Arabic course,
The original Arabic number system looked like this, the one we now use.
It was designed so each character had the corresponding number of angles to the number, so the number 1 has 1 angle, 2 has 2 angles, 3 has 3, 0 has none etc…
It is so obvious now, I’ve always assumed its one of those things that just is, with no logical explanation, but here it is, perfectly simple and satisfying.
(From tumblr, via thepowerofmoonlight. Visit the Noakes Library Archives and Bulletin Boards tumblr here. )
a cartoonist in Kekionga 
Now THAT’S straight out cool, and something that’s completely obvious….once it’s pointed out to you. It also shows the history and raison d’etre for the “European” 7 with crossbar, something I’ve been mildly curious about for years.
My thanks to Iowa!
She finds the most interesting stuff, doesn’t she. I spent many years in high school and college making the Euro 7– it took me almost as long to train myself out of it. (And don’t get me started on the Greek E.)
But who makes a “9” with that curly tail at the end these days? I know the Europeans still write their 1s and 7s that way, but that 9…
It’s a little far fetched, I’ll admit that, and certainly not in synch with current handwriting styles. Such as they are.
C’mon now Wolf, not many folks make their fours with a closed angle up top either.
Once the Arabic numbers came into common usage folks started to shorthand all of the different digits. 9 is the most simplified because it’s the most complicated to begin with.