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### Course: Pre-algebra>Unit 6

Lesson 1: Parts of algebraic expressions

# Why aren't we using the multiplication sign?

In algebra, representing multiplication with variables can be tricky due to the similarity between the variable "x" and the multiplication symbol. To avoid confusion, use alternative methods like 2⋅x, 2(x), or 2x. Practice evaluating expressions by substituting given values for variables and following the order of operations. Created by Sal Khan.

## Want to join the conversation?

• at , why do mathematicians use "X" as a variable more often that most?
• x is actually the latin replacement for the arabic word that means "unknown" or "something." Here's a short video about it on Tedtalks: http://www.youtube.com/watch?v=YX_OxBfsvbk

Hope you foound this interesting :)
• What is preferred the dot or the x
• Once you get to Algebra, the x should no longer be used for multiplicaition, it is reserved for a variable. So the dot is now preferred, or use parentheses or an asterisk (*).
• Soooo... why are we ever taught "x means multiplication" at all?! Wouldn't it be easier if we just always used the dot? It's not like one is more intuitive than the other.
• That would be great. Maybe the issue has to do with abstractness. When people are young, they are very much concrete thinkers - what you see is what you get. Later in 5th to 7th grade, they are able to start thinking more abstractly. Perhaps using a dot is too abstract for the young compared to an x. This is only a thought, it may not mean anything.
• Why do most people use x instead of other letters like p or s or even q?
• It's just a common variable to use. Many people use p, s, q, and every other letter (you'll even see Greek ones in geometry!).
• Why couldn't you just use a different symbol than x?
• You can use any letter, but i recommend that you shouldn't use o because it looks like 0.
• is this correct way to solve 7+4b b=3

7+4b
= 4*3
=12+7
=19

is there another way I can solve this problem
• yep,that's the way I do the equation. But I do that more explained.Otherwise I can't understand the question.
7+4b,b=3
=7+4*(3)
=7+12
=19
only a little bit explained.
• At Sal says we can use a dot for a multiplication sign instead of an x. Why do mathematicians use a dot, and not some other sign?
• If you're asking why we use the dot specifically, it probably just arose because of its simplicity. We multiply things a lot in math, and mathematicians like to be efficient when they write. The dot (it's actually called an "interpunct" to be more specific) is so simple and short to write, that's probably why we use it instead of another symbol.
• tbh i never used the ' x ' for multiplying numbers, my 4th grade teacher told us that in later years, we were gonna be doing more complicated math, and it would be a lot more easier to use the ' * ' instead so that was rlly helpful
• Also in coding you use the '*' to multiply avoiding the 'x' problem, beacuase you can use X has variable to.

The thing is that in coding variables are a wider concept.
• why did the teachers tell us to use a dot as a multiplication sign instead of the x