Okay kiddo, let me explain what capital sigma notation is in a simple way.
You know how sometimes you have to add a lot of numbers? It can get pretty tiring to write them all out. That's where capital sigma notation comes in!
The capital sigma symbol looks like an "E" with a fancy tail on top. It's used to show that you're adding up a bunch of numbers.
For example, instead of writing 1+2+3+4+5, you can write it as ∑(from 1 to 5) i. The "i" means you start at 1 and add one each time until you reach 5. So you end up with 1+2+3+4+5!
You can also use capital sigma notation to make more complicated sums easier to write. It's like a shortcut for adding things up!
So that's it - capital sigma notation is just a fancy way of showing that you're adding up a bunch of numbers. It may look confusing at first, but it's actually a very helpful tool.