 So, one of the first things we have to look into is what is a table? A table is a little different than your traditional four legs, you put things on it. It's not like a desk. When we're talking about a table inside of a computer, what we're actually talking about is sort of a grid-like structure that looks sort of like this. And why this is important is because Excel sort of expands on the idea of tables by including in a way for us to reference any particular cell. So let's take a look at this guy right here. This guy right here, this is known as a single cell inside of my table. Now, how do I reference this cell versus this guy, this blue guy I got over here? How do I do that? Well, it's also a cell. So what Excel does is it actually starts to introduce our sort of referencing styling. For example, each one of our columns, our vertical sections inside of a table are given a capital letter, A, B, C, D, and E. Now, every one of my horizontal sections, they're given a row number, one, two, three, four, five, and six. The reason why they do this is now I can play battleship effectively. I can look at any one of my combinations of letters and numbers, and I'm able to then pinpoint which cell I'm referring to. Now how do I do that? I can't just arbitrarily say them in any combination. I can't just say 1A, for example. 1A doesn't do anything. 1A will actually give me an error in Excel. But if I was to say I want to reference this cell right here, I would first start with my column. Well, my column is the A column. So let's see where I can put this, let's boom, right about there. So I'm looking at this cell right here. This is known as my A column. And then it's on the fifth row, so it becomes A5. If I'm looking at that blue cell that I did earlier, that's D going all the way, so D4, because we're on the fourth row. So you might remember taking algebra once upon a time. Algebra introduced this idea of variables. Now why is that important? Why is he starting to bring up math all of a sudden? Well, one of the crazy things about Excel is it is, in fact, algebra. It's a really powerful form of algebra. So let's actually kind of look at a bit of an example. Let's say for example, I have inside of one of these cells something like subtotal. The word subtotal is perfectly fine. Let me put that T in. This is considered text. Now text doesn't do anything, it's just text. Then let's say we add in a word called tax, all right? Nothing crazy just yet, and I'm sure you can guess what would come next, total. So the reason why I mention this is obviously what we can do inside of Excel is we can start to make ourselves a glorified calculator. So my subtotal, say for example, I went out to eat last night and I had a pretty good meal. It was pretty filling, but it was around the $12 range, $12.50. So now we look at that and we go, okay, well, what else do you have to apply? It's not just $12.50. We know how things work here in the States. There's always that wonderful thing called sales tax. And so there was a 7%, and I'm just going to denote this with a dollar sign so we can kind of indicate this, that's a dollar sign, and we'll say that we had a 7% sales tax. So now some of you are pulling out your tip calculators and don't worry about that and you're cheating and you're pulling up the calculator program. Again, it's not necessarily up to us. I don't need to know what this actually is. Instead, what I want to know is how much is my total? Well, if we look at this for a second, we can actually take a look and we can see that we have two numbers. I have a subtotal that's very important, and that cell range or that cell reference for my subtotal is B1. I have another cell reference for my tax that is B2. Let me make that one a little bigger, B2. So if we think about for a second what I need to do, the first thing I would have to do is I start inside of my Excel spreadsheet with the equal sign. That equal sign tells Excel it's about to do a formula. It's about to do a math equation. Instead of just dealing with numbers and text, it's going to deal with calculations. So the first thing is I have to put in my subtotal, B1, reason-wise because obviously I apply the tax to the subtotal and then I add whatever that is to my subtotal. I wish it was just whatever the tax time subtotal was, but that's unfortunately not how the world works. So the next portion, like I just said, is I have to apply this. Now I'm going to use PIMDOS. Please excuse my dear Aunt Sally and I'm going to put in some parentheses here. And so we see that we have a 1250. Again that was B1. I don't want to use explicitly 1250 because what happens if that changes and it will in just a bit. B1 times, and we'll put the little asterisk here for that, times B2. Just like with my 1250, I don't want to put 7% in here. I want to put the reference to 7%. That way if 7% changes, you know, no taxation without representation, massive uprising and sales tax is obliterated from the United States. Cool. Awesome. Well, I need to make sure that my spreadsheet works. So all of a sudden, this math equation, this is going to go and it's going to look and it's going to say, oh, hey, what is B1? And it's going to grab over here and it's going to grab 1250 and it's going to do the exact same thing. It's going to say, oh, what is B1? Now it doesn't know it, so it's going to continue to do it. And then over here, it'll say what is B2? Well, it's going to grab whatever B2 is. And then it takes all of those numbers and it places them in. And then, and only then do I get the math equation of, let me scroll down a little bit. Only then do I get the math equation of 1250 plus 1250 times 0.07. Now I am going to cheat, obviously, and that 12.5 times 0.07. Not too terribly crazy. It's about 87 cents. So this translates to 87 cents. We'll round up. Why not? 86 cents. So 1250 plus 86, what we should see in the total is 1336.