Hey, and welcome to the Short Stuff. I'm Josh, and there's Chuck, and this is short Stuff, and we are going to talk about something that has been overlooked for far too long, which is the origins of the plus minus multiplication, division and equal symbols.
I thought this was really cool by the way you put this together with help from FASCO, cal Tech, Science ABC, among other places. And I had never thought about this stuff because I'm not a math person, but I love origin stories, and I thought this is really neat, especially the fact that these symbols came about to begin with, because people before they had these. You wrote out a math problem like this long word problem, but not like you know, a train's traveling in this direction kind of thing.
It's more like I have divided ten into two parts and multiplying one of these by the other. The results was twenty one. Then you know that one of the parts is thing and the other is ten minus thing.
Right. That was an excerpt from a ninth century algebra book by the mathematician Mohammed ibn Musai al Kharazmi. I'm pretty sure that's his name. Today you would take that same formula and write it out as x times ten minus x equals twenty one.
Yeah, so simple, that's it.
And that reveals why these things were so important. It just saves you so much time. So not only did it make writing an algebra book that much more attractive, it made teaching it that much faster. You might not have necessarily learned it any faster, but you definitely could teach these things faster with these notations rather than writing it out. And I also saw check that some of those sentences that they would write, some people would put
it into verse metered verse like poems. That takes a lot of time, and it's unnecessary.
Yeah, and especially at the time when you're writing with eagles, feather and an ink. Weell sure, you know what I mean.
That really drags too.
It's not like you're just dashing this stuff off with a pencil.
Nope.
So some folks came along and changed all that.
According to the v NR Concise Encyclopedia of Mathematics hot Read, the origin of the equal sign goes like this. A man named Robert record or record A was the royal court physician for King Edward about six and Queen Mary, and a very influential mathematician in Wales, and he got tired of writing out equals over and over, so he thus proposed the equal sign because it is two little equal lines, and that's parallel equal lines.
And this I never thought it, but it's brilliant.
Yeah, he said, a pair of parallels or twin lines of one length, and then he spelled. He shows what he's talking about, because no two things can be more equal. And there's a lot of extra vowels in those words, but yeah, he gets the point across. And he was saying, like, this is such a great time saver. I'm so tired of saying is equal to? And he wrote it in a book called The Wetstone of Wit, And of course a whetstone is what you sharpened things with, so it
sharpens your wit to read this book. I love that title, and it actually became very influential and well read as far as sixteenth century math books go. And Robert Record is credited with coming up with the minus symbol and introducing it to his people back then.
The equal sign.
You mean what I say?
Minus sign? Oh just wait, chuck, all right, well we're there.
Plus and minus are what we use to indicate adding something and subtracting something. As everyone knows they come. The terms themselves come from Latin, where plus means more and minus means less. And the other thing is the plus symbol itself is also from the Latin word et et, meaning and like this and that equals that, which is pretty great. So at one point there was a French philosopher named Nicole ors Me from the fourteenth century who used that plus sign as a shorthand for et, which
is what they used to write. And at first it didn't take right, I think, like people weren't universally accepting this.
Yeah, it wasn't until like the sixteenth or seventeenth century that it started to really kind of take off. I think the sixteenth century, Okay, And apparently there was competition at first too, that it wasn't just the plain old plus sign that equal cross, that there were other crosses in the in the running too, including the Maltese cross. It's a great looking cross, yeah, but it takes a lot more time to write the Maltese cross out than it does to make a plus symbol, and the whole
point of these things was to save time. So everybody said, yeah, Maltese cross, we like you. But we're gonna go with the plus sign.
That's right.
So that's plus, we got equals, we got plus minus. Now in Europe there was an Italian mathematician named Luca Pacioli, and Luca was using the symbol P with a little line over it for plus, an M with a little line of it over it for minus. And no one's exactly sure, but it seems to be that the M was just dropped right, and then the minus sign, because we already had a plus sign, became the minus sign.
Yeah, so you don't need the plus sign forget you P with the tilbey over it. We're gonna take the M instead. And it was it wasn't Robert Record who came up with that, but he was the one who introduced it.
To England, right, And I never knew it was called it tild.
I didn't either that line over the P or the M. Yeah, I think that's what they call it, so yeah, And I don't know if it's the minus sign itself is called that, or if it has to be over the letter to be called that.
All right, Well, there are a couple of other words that I did not know coming up right after the break, all right, we're gonna wind it out with the multiplication
symbol and the division symbol multiplication. If you say it's a little X, you're incorrect because it is not an X. It's actually called the Cross of San Andreas because X. Well not because, but it would be very confusing because X is already a thing in math, Like you're solving for X. X represents something in math, So it's it's actually incorrect to say it's a little X.
Yeah, if you do that at a math conference, they will find the nearest fire hose and flood you mercilessly with it.
They will.
So, yeah, that makes total sense. And it was a guy named William Autred who was writing in I think the sixteenth century, like the sixteen thirties, and he was the one who introduced it. He's credited with this. But the people at Science ABC went to the trouble of digging up the fact that there's an anonymous appendix in a translation of another book of logarithms from sixteen eighteen where the Cross of San Andreas is first used.
Okay, so, but he introduced it in before that, right, no.
After, But since it was anonymous in the appendix, they don't know who to credit it with, and I said, you need to win today. We're going to with that.
I mentioned before the break that there were a couple of more words that I didn't realize were words, and that is the the division symbol that apparently I didn't even know this is not even really used anymore officially, which is to say, the line like the minus symbol with a dot above it and a dot below it in the center, that is actually called an obelis.
Yeah, that symbol. You know what, it reminds me of of that calculator that was shaped like a big plastic owl. Oh, that's what I associate that with. I remember those, But I didn't know it was called an obelis either. And I also didn't know that obelis is an old Greek word for sharpened stick, and that that division symbol, the obelis is supposed to represent a small dagger.
Yeah, it looks like one.
So I guess what it's doing is it's cutting in half. It's cutting a portion out. Ah, that's the only thing I can come up with.
Okay, I like that though, sure.
And we can thank Johann Ron, who's Swiss not Swedish, who started using it all the way back in sixteen fifty nine.
That's right.
The other word I did not know is the what is now the backslash symbol for division is called a either a fraction bar or a solidus.
Yeah, didn't know that either.
I didn't know that that was the exclusive thing. Now, this is how out of touch with matth iron.
Yeah. Apparently the ISO, the International Organization for Standardization, who aren't familiar with how to create an acronym. They said that you could only use the solidus or the fraction bar to indicate division, and that the obelis is out out out. But Science ABC said, don't worry everybody. Listen, if you go on to your keyboard, you know what's weird. I haven't tried this. Did you try it?
No?
I'm going to try it right now. Why don't you go ahead and tell everybody what you're supposed to do and I'm going to try it myself.
Chuck, Well, what you do is you hold the alt key on your keyboard and then press two four to six on the number pad.
And what do we got? My friend?
I think maybe you have to press it at once, hold on two four six. You got lies? That's what you got Chuck thirty lies.
Oh well, let me try then you talked for a second.
Okay, So I'm going to do it again, two four six with all pressed at the same time in Microsoft Word. The current version of Microsoft Word won't do it.
I don't even know if I have Word on this laptop.
The thing that gives it away for why I think this might not be correct any longer, is that they mentioned that you press the numbers two four six on your number pad. Remember when numbers used to be off to the side on a keyboard and their own thing.
Well, I've got a keyboard like that. Okay, let me let me try it for you. So all to two four six.
Yeah, I think at the same time.
Oh that's hard to do. I'm trying to, like fingering a weird guitar chord that didn't work alt two for six.
Right, this is just bs.
They got us, Chuck. They got us as good as Debbie Ranka did with that whole thing about Judas spilling the salt shaker in the Last Supper.
Wait, let me try one more thing, two for six. Now it's not working.
Okay. Well, I'm sorry everybody that we misled you, but I'm glad we worked it out so you don't have to email us about it.
Yeah.
Maybe someone knows though, and can tell us what we're doing wrong.
Yeah, we love hearing that, and while we wait for you to write in short, stuff is out.
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