Variables are scary because no one ever tells you what a variable is. Until now, you’ve mostly been dealing with particular numbers. Multiplying, dividing, adding, subtracting, and now they want you to do math with letters?! How do you add two letters? Here’s a little secret. The letters are numbers!
A variable is a symbol representing a number
Which number does the letter represent? 5, 500, 5 million? Well, that’s the beauty of using a letter. Until we figure it out, x could be any number. That means x acts the same way as all other normal numbers. For example, let’s say you want to add x to 2. It’s the same adding 3 to 2. On a number line, you start at 2 then count 3 units. Wherever you land is the answer.
It’s the same when adding x to 2. On the number line, start at 2 then count x units. Whatever you land on is the answer. We won’t know what number we land on until we know what x is, but that’s okay!
It’s also important to know that variables don’t vary. We might not know what x represents, but it still only represents one number. So, why not just use the number?
Well, most numbers behave the same way. Therefore, when we want to make a statement about every or any number, we use x. Instead of solving one particular problem with specific numbers, we can solve a whole bunch of problems at once then take a nap.
For more helpful tips on algebra I, read part 2 of this series and check out Brightstorm Algebra.