What are Variables in Math? - Definition & Examples

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  • 0:05 Defining Variables
  • 1:42 Using Variables
  • 2:54 When to Use Variables
  • 3:42 Lesson Summary
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Lesson Transcript
Instructor: Yuanxin (Amy) Yang Alcocer

Amy has a master's degree in secondary education and has taught math at a public charter high school.

Variables are seen in almost all math applications beginning with algebra. In this lesson, learn why variables are not something to be afraid of or some concept that is impossible to grasp. Learn what makes them so useful to mathematicians and to you.

Defining Variables

Variables are nothing more than a placeholder. They stand for things that you want to find out but don't have the answer to yet. Think back to grade school when you were learning addition and multiplication. Did your teacher ask you, 'What plus two equals five?' Well, when the teacher uses the word 'what,' she actually used it as a variable. The 'what' is something you wanted to know but didn't have the answer to right away.

Now, of course, you wouldn't even blink at that question. You quickly would answer 'three' and not even think twice about the 'what.'

In math lingo, there is a formality when it comes to variables. When you write them, instead of using the word 'what,' you would use letters. You can use any letter you choose. Typically, we stick to the English alphabet but technically, you can use any easy-to-identify symbol as your choice.

The two most common variables you will encounter in your schooling career are the variables x and y. Don't ask the reason why these two are the most popular. They just are and have been in use for so many years past. They are easy to spot and to identify, which makes them ideal candidates for a wide variety of mathematical applications.

Just because x and y are the two most popular variables doesn't mean you have to use just those two. You can use anything you wish. You have numerous choices to pick from.

Examples of variables

Any letter you can think of can be used as a variable. They can be uppercase or lowercase. When you get into more complex math applications, you might have several variables in one equation, so your ability to use more than one variable at a time will become important.

Using Variables

Variables have always stood in the place of an unknown answer. Their use remains the same. They always stand for something you want to know but don't have the answer to. With the aid of variables and algebra, you can find out the answer.

Going back to grade school again, let's look more carefully at the question 'What plus two equals five?' We now know that the 'what' stands for a variable. We also know now that we can choose any letter for our variable. So, let us choose x. Why not? It's an easy letter to choose and there is a phrase that goes, 'X marks the spot.' That's easy to remember.

Using a variable part 1

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