Where do math symbols come from? - John David Walters

Math is full of symbols: lines, dots, arrows, English letters, Greek letters, superscripts, subscripts ... it can look like an illegible jumble. Where did all of these symbols come from? John David Walters shares the origins of mathematical symbols, and illuminates why they’re still so important in the field today.

Lesson by John David Walters, directed by Chris Bishop.

Thank you so much to our patrons for your support! Without you this video would not be possible.
Neil Harrison, Srikote Naewchampa, Benjamin & Shannon Pinder, Govind Shukla, Tejas Dc, Khalifa Alhulail, Faiza Imtiaz, Martin Stephen, Tyler Yoshizumi, Jerome Froelich, Jose Schroeder, Dan Paterniti, Jose Henrique Leopoldo e Silva, Mullaiarasu Sundaramurthy, Antinfinity, Gaurav Rana, Elnathan Joshua Bangayan, Elizabeth Cruz, Caleb Ross, Michael James Busa, Quinn Shen, Joshua Plant.

[Marcopolo]

Wow, what my middle school math teacher meant by “Mathematicians are lazy” makes COMPLETE sense now. I never put thought into what he said.

[CaptTerrific]

This was kinda disappointing... we only actually got the answer to the question "Where do math symbols come from?" for 3 symbols: =, +, and !

[thesuomi]

It's interesting how there are still different ways of writing some of these, •, * and x are used for multiplication etc.

[gigglysamentz]

The division sign that we're all wondering about is called obelus and was first used for division by Swiss mathematician Johann Rahn in his 1659 book

[TheCanno]

''English letters'' that hurts me a bit

[charliecastillo]

If math class covered more history like this I probably would have liked it more

[Yathuprem]

Awesometh videoth. I gave u my liketh and shareth.😂

[dergrosserobini]

I'd like to add a few things: the symbol for the square root √ and the integral ∫ come from the latin letters r for root and s for sum respectively. The minus sign - is what's left of a tilde written over the letter m indicating substraction, π is the greek p for perimeter (of the circle with diameter 1). Most other signs, like * and /, are fairly new and were invented by mathematicians.
The alleged origin of the digits is also very interesting: 0 was the original ten, and is was written a little up, so that 9 and 8 were that circle with one and two little lines coming from its bottom. The 5 was the same circle written low, and with a horizontal line over it for disambiguation. The 6 and 7, again, are that low circle with one and two lines at its top. 1 to 3 are series of straight lines forming just as many angles as their value. 4 was once just a kind of cross, thus forming four angles, but the horizontal line sort of slided to the left a bit and was bent up at its left end. Better google these again. That's all I can tell :D

[crisk]

I didn't know I wanted to know this until now

[TheTexas]

They’re called Latin Characters (or letters), not English letters

[EweChewBrrr]

That was really interesting but I wanted to know more on how the symbols were invented. The divided by symbol was what I was waiting for.

[virgile]

disappointed that there wasn't a small explanation of ÷

[alastairhewitt]

One of the many things I love about Khan Academy is that Sal always reminds us of what the symbols mean, no matter the level of the course. Makes learning so much easier.

[kathryncarter]

I think vertical "equal" signs could get easily mixed up with one & sevens if you're really into a significant number problem.

[ryandarshen]

2+2 is 4, minus 1that's 3, quick maths

[AmateurContendr]

"Where do math symbols come from?"
Only explains the origin of two symbols.

[bechirbrahem]

Actually the symbol of the square-root has a reason why it is that shape :
root in arabic is جذر and its first letter is ج which if rotate it you get the modern symbol

[hymnsoncheung]

3:52
Those aliens are so adorable like my teeth

[cilglwb]

수학기호를 만드는 과정이 어렵고 잘 갖추어진 시스템인 것이라고 생각 했는데 잘 갖추어진 시스템이 아닌 단지 유행 일뿐이라는 것이 충격적이었습니다. 또 기호의 중요성도 배웠습니다. 유익한 동영상 감사합니다.

[wophful]

“Kind of like a meme” you mean literally like a meme. That’s the definition of meme.