Summation notation is a simple way to show how to add up a list of numbers. It is often shown using the Greek letter sigma, which looks like this: $\Sigma$.

This notation makes it easier to write math ideas and helps everyone understand them better.

For example, if we want to add the first $n$ whole numbers, we can write it like this:

$$\sum_{i=1}^{n} i$$

In this expression, $i$ is just a number that starts at 1 and goes all the way up to $n$.

Learning about summation notation is really important in pre-calculus. It sets the stage for studying sequences and series, which are important parts of math.

When students understand summation notation, they can add numbers more easily and get ready for calculus and other higher-level math.

Overall, knowing how to use summation notation helps students see patterns in numbers and improves their math skills.