In Algebra, we use letters as variables to represent unknown or missing numbers in expressions and equations. But usually our go-to letter for variable is x. Why is that?

I once heard a podcast episode (about math of course) explaining how and why we use x as our primary variable for an unknown value. I was so intrigued because it was talking about how Algebra started in the Arabic language with Muhammad Al-Khwarizmi in his book Kitab al-jabr wal-muqabala. In Arabic the word al-shahan means "unknown thing".

However when scholars were translating to Spanish, there were no sounds for "sh" so they went with the sound "ck". When translated to classical Greek, this sound corresponds with the sound "chi" which matches the symbol X, and was later translated to the Latin letter x. (Apparently this story is being challenged due to little documentation.)

There's also the story of Descartes and his work La Géométrie who used lowercase letters in the beginning of the alphabet (a, b, c) to represent KNOWN numbers and lowercase letters at the end of the alphabet (x, y, z) to represent UNKNOWN numbers. However, the reason why x was chosen as the most dominantly, go-to letter for a variable is credited to his printer (a person at this time) who said that x wasn't used enough and wanted to give it some exposure.

So there you go. Variables are fluid and can really be anything. At the elementary school level I've seen variables (unknowns) as just blank spaces. I honestly like x because it looks like no other letter or number, which makes it hard to lose in your work, and it's easy to write. Variables can literally be any symbol, so don't let x get you caught up.

What would you use as a variable instead of x? [Comment Below with your choice⬇️] .

As an Uber driver I encounter so many different people with various interests. Sometimes I find out that they have an interest in math, and I get really excited! .

One day I picked up this pharmaceutical sales guy and he was relating how he tried to help his child understand variables.

He said x is our go-to variable we always see, but you could also just as easily use flowers and smiley faces.

We can use anything to represent a variable (or unknown number).

🅰 Do the images change how you are able to answer these problems? Let me know below.

🅱 What answers did you get and how?

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Latreil Jackson is a former math teacher turned math coach and course creator. She's known for her ability to teach math through real life connections and illustrations, as well as mentor students to math confidence.

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