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Have you ever looked at a math problem and wondered, "If this is a math problem, why are there letters?"
y = mx + b
![](https://images2-cdn.storyjumper.net/transcoder.png?trim&id=7b5ad96502&maxw=256&maxh=256)
Why are there letters in math?
![](https://images2-cdn.storyjumper.net/transcoder.png?trim&id=34-09e517xf9o-5ra30ozwf&maxw=512&maxh=512)
Today we use letters in math to represent a number that is unknown or that can change. We call these variables.
The word variables comes from the latin word variābilis. "Vari" means "various" and "-ābilis"means "-able." Together they mean "capable of changing." [1]
But mathematic didn't always use letters. Back in the 7th century, the Indian mathematician, Brahmagupta used colors to represent unknowns. [2]
![](https://images2-cdn.storyjumper.net/transcoder.png?trim&id=0aa1b8922&maxw=68&maxh=68)
![](https://images2-cdn.storyjumper.net/transcoder.png?trim&id=beb4d82122&maxw=68&maxh=68)
So why do we always have to solve for x?
In algebra we are typically asked to solve for x. But why not ❄︎ or ✆︎? There are actually several theories, but the most enjoyable one is that it is actually a translation mistake.
![](https://images2-cdn.storyjumper.net/transcoder.png?trim&id=beb4d82122&maxw=68&maxh=68)
![](https://images2-cdn.storyjumper.net/transcoder.png?trim&id=0874366302&maxw=256&maxh=256)
Algebra comes from the the ancient Arab world. In fact, the word algebra is a twist on the Arabic word al-jabr, which is part of the title of a book on mathematics by Muhammad Al-Khwarizmi from the 800's.
In Arabic, the word al-shalan means "unknown thing," but when Spanish scholars tried to translate the word, they had to use the Greek letter chi (X), because spanish didn't have the needed sound to pronounce "al-shalan" correctly. Later, when the Spanish books were translated into Latin, the Greek chi (X) was replaced by the latin X.
![](https://images2-cdn.storyjumper.net/transcoder.png?trim&id=35-hfj6t4si0f-5ra3tdvmh&maxw=256&maxh=256)
And now we solve for the unknown thing, x, because Spanish didn't have the sounds needed to pronounce "al-shalan" correctly.
This story is fun, but it may not be true. There isn't any evidence to support it. Why do we us x as our common unknown, especially more than other letters like y, and z? Nobody really knows. We just do! [3]
4x + 7 = 15
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![StoryJumper Logo](https://www.storyjumper.com/images/cloud-logo-250.png)
Have you ever looked at a math problem and wondered, "If this is a math problem, why are there letters?"
y = mx + b
![](https://images2-cdn.storyjumper.net/transcoder.png?trim&id=7b5ad96502&maxw=256&maxh=256)
Why are there letters in math?
![](https://images2-cdn.storyjumper.net/transcoder.png?trim&id=34-09e517xf9o-5ra30ozwf&maxw=512&maxh=512)
Today we use letters in math to represent a number that is unknown or that can change. We call these variables.
The word variables comes from the latin word variābilis. "Vari" means "various" and "-ābilis"means "-able." Together they mean "capable of changing." [1]
But mathematic didn't always use letters. Back in the 7th century, the Indian mathematician, Brahmagupta used colors to represent unknowns. [2]
![](https://images2-cdn.storyjumper.net/transcoder.png?trim&id=0aa1b8922&maxw=68&maxh=68)
![](https://images2-cdn.storyjumper.net/transcoder.png?trim&id=beb4d82122&maxw=68&maxh=68)
So why do we always have to solve for x?
In algebra we are typically asked to solve for x. But why not ❄︎ or ✆︎? There are actually several theories, but the most enjoyable one is that it is actually a translation mistake.
![](https://images2-cdn.storyjumper.net/transcoder.png?trim&id=beb4d82122&maxw=68&maxh=68)
![](https://images2-cdn.storyjumper.net/transcoder.png?trim&id=0874366302&maxw=256&maxh=256)
Algebra comes from the the ancient Arab world. In fact, the word algebra is a twist on the Arabic word al-jabr, which is part of the title of a book on mathematics by Muhammad Al-Khwarizmi from the 800's.
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