Discussion:  All Topics in Algebra 
Topic:  Is "variable" confusing to students? 
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Subject:  RE: Is 'variable' confusing to students? 
Author:  ellen4444 
Date:  May 8 2009 
the equation true. If anything is confusing it's that we don't tell students
what is meant by directions like "solve" and "evaluate".
On May 8 2009, Susan wrote:
> I'm trying to establish the differences among the following three
> things:
3x + 5
11 = 3x + 5
y = 3x + 5
The first is an
> algebraic expression containing the "variable" x. In this case, the
> variable x can take on any value. It “varies”.
The second is an
> equation of one variable. We call x a variable but truly it doesn't
> vary. It is just an "unknown". We can solve for x and determine it
> must equal 2.
In the final case, we have two variables and they
> do 'vary' depending on each other’s values.
Should we call the x
> in the second case an “unknown” and not a variable? I’ve seen
> books say, “solve for the unknown”.
I think we confuse students
> by calling x “variables” in all of these cases when in case 2, the x
> does not vary at all.
 
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