Before we begin adding polynomials, we are going to review the definition of like terms.

## Like Terms

Like terms are two or more terms that have identical variables, and possibly different coefficients.

Take a look at the following examples: It's very important that you understand this definition of like terms as you begin working with polynomials.

When you add polynomials, you are simply going to add the like terms. There are two methods that you can use to add polynomials: the vertical method or horizontal method. I will show you both methods, so that you can choose the one that is most comfortable for you.

For example 1, I will use the horizontal method.

## Example 1: Adding Polynomials Horizontally Did you notice how we simply rewrote the problem with like terms together, and then combined the like terms? Now, I'll show you the vertical method.

## Example 2: Vertical Method You may like the vertical method because you are used to adding numbers vertically. Remember, you will end up with the same result, so you choose the method that you like best.

Let's take another look at an example using the horizontal method. Now we'll look at an application of this skill and use the vertical method to solve.

## Example 4: Find the Perimeter Great Job! You should now be ready for subtracting polynomials.