…with dots (variables) where the numbers would be. I can’t believe I never saw that before until it was just pointed out to me.
Also note how / is not just a symbol; it’s a literal representation of the expression. When a fraction like one divided by two is expressed as 1/2, the / is literally separating (or dividing) the one from the two. The one is one side of the division line and the two is on the other. It’s like a border wall between them.
I noticed that as a schoolboy and I remember feeling very pleased with myself. More recently I learned that the symbol is called an obelus, although that’s also the name for a dagger symbol, which is confusing.
I think Mexico paid for it.
It’s certainly a divisive issue.
I’ll be damned.
Change it to a slanted line, and you have a percent symbol. Although dot / 100 might make more sense there…
Hey, this issue now has its very own clickbait! http://www.guacamoley.com/the-scoop/2017/09/13/Z2ruQov/man-discovers-what-the-division-sym The headline annoyingly concludes that “the Internet” didn’t know it either, based on a few dips**ts on Twitter being surprised, but I suppose he who clicks on clickbait deserves what he gets.
It seems a guy named Abdul tweeted about it a day or so before this thread though. Is that where the OP saw it? https://twitter.com/Advil/status/907092348345241601
No snark intended: Ain’t it cool when you figure out something on your own? 
No, really. I didn’t figure out calculus on my own, but I was a D student in math and figured out, when determining the area of a fillet (spandrel, apparently), if I drew it ten times scale, drew a bunch of rectangular slivers, then treated the leftovers like triangles, I could get damned close. Impressed the hell out of myself. 
Note: My time was poorly supervised.
Yes when I was 12 (in the early 90s) I figured out 1+2+…+n=n*(n+1)/2 by thinking about square tiles. I remember wondering whether I should hurry to announce this discovery before someone scoops me.
I remember seeing that in middle school, but I also saw this a few days ago on Reddit. The order usually goes Reddit –> Clickbait site –> SDMB. It’s nice to see the universe working properly.
Square tiles? You lost me.
Well, I was looking at square tiling and thinking “one tile, then two tiles, then three tiles…”, stacked like this:
so I thought that it looks like half a square (nn/2), plus some extra to account for one half of each tile on the diagonal, and I got (nn/2 + n/2)
Another one i figured out a long time ago, about recognizing the greater-than, less-than signs, > and <. Those seem to confuse a lot of people.
Think of them as starting out as an equals sign, with the two horizontal lines =. Then they got pushed, so that the larger side is farther apart and the smaller side is closer together (touching, actually). That single rule works for both of them, and I find it really easy to visualize and remember it.
Yeah, at the very least, it literally depicts things being divided.
Trouble is, in some parts of the world (Denmark, in my experience), they use something very similar as the symbol for subtraction. On reading up, I believe what I saw in use there is the ‘commercial minus sign’, which looks a bit like a %, but with dots instead of circles, however, in handwritten text, the folks I observed were writing minus as a horizontal line with one dot above and one below.
There’s a (brief) discussion of this symbol, including one answer that says why they use that symbol, on stackexchange:
One of my teachers (HS Chemistry, I think) said that the division sign was made up of two signs. The “/” and the “:”. You used the / for expressing as a fraction, the : for expressing as a ratio.
I did indeed see it on Twitter so consider me one of those dipshits 
I liken it to the Arrow in the Fed Ex symbol. It’s not there until you see it.