What is a variable?

Question

Is it just X or Y or whatever?

Answer 1

A variable is simply the term used to describe an unknown quantity. For example, if a farmer has a certain number of acres of land, but you don't know how many acres he has, you could say he has "x" acres. If you know some more information, you may be able to solve for this value. You can name it whatever you want ("x" or otherwise), but keep in mind there are two main types of variables:

 

Independent variable:  This is what you usually see as "x". The independent variable means just what it sounds like: It's independent. It doesn't depend on any other value. It can be anything you define it to be, based on what type of value you're trying to solve for that is "unknown".

 

Dependent variable: This is what you usually see as "y". The dependent variable also means just what it sounds like: It depends on some other variable. The independent variable ("x") is usually what determines what the "y" value is.

 

For example:

 

y = 3x + 4

 

x is independent, because we can make x whatever number we want, without it being restricted by some other value.

 

y is dependent, because whatever we made x will determine what value y will then be.

 

Hope this helps!

Answer 2

Will M. gave a great answer, but maybe you need something simpler.

 

A variable is anything you use to stand for something that is either unknown or that changes. You can use x or y as a variable name - or a or b or c, or even a word such as miles. 

 

If you have 2 + 3 = ___, you can replace the blank with a variable name: 2 + 3 = x. It just holds the place of your unknown amount.

 

(Or in computer programming, it might hold information that changes. For example, the variable firstName can be used to collect the names of all the students in your class.) It changes because firstName for the first student in the first row might be Jesse and the firstName for the second student in the first row might be Lindsay)