In this screencast, I'm going to explain to you how to name cells and cell ranges, a best practice in Excel. The example I'm going to be working through here first is in a file called Savings.xlsx. It's just a simple equation here where we have a principal amount. That's the amount that you invest in a bank. We have an interest rate I, and we're investing for n number of years. So let's just put in some data here. Maybe we invest $200 at an interest rate of 5% for 10 years. By the way, if I wanted to change this to a percent you can always go up here and change it to percent. Now, in a previous screencast you should have learned about absolute and relative cell referencing. You should have learned that we can make absolute references by clicking on a cell and pressing the F4 key to make it completely absolute. Or you can toggle to make it mixed addresses and back to relative. Now, the best way to work in Excel is to name absolute references. If we have constants or values in here that are never going to change, then it's best practice to name them. So for example, I'm going to name this a variable called P because that is the variable name. It's the principle. The easiest way to name single variables is to go up here. There's this box up here in the upper left called the name box. So if I want to name that value in cell C5, if I want to name that capital P, I can just type capital P and press Enter. And if I use that variable any other places on the worksheet, I can type in =P and you see that P, capital P, is an absolute reference that always refers to cell C5. I can use that named variable in a mathematical formula. I'm going to do the same thing for interest and n, the number of years. So I'm just going to click in cell C6, I'm going to put in variable i and I'm going to do the same thing for C7. That's going to be lowercase n and you see that those are all named now. And by the way, if you're anywhere in a worksheet and you want to know which cell corresponds to a named variable, you can just type into the name box something like capital P as just an example and it'll go to that cell. Now in the cell here, in cell C9, I'm going to put a formula, just this formula up here to calculate S, and you'll learn more about syntax in the next week. We put in here =P*(1+I) and you see that instead of using cell addresses we're using these named variables. And then I'm going to take it to the power of n, and you see that it's color coded here and we see the corresponding cells where P, i and N are defined. So then I can press Enter and it does that calculation. So that means after 10 years at 5% interest $200 will become about $325. Let me real quick show you how to edit. So if you want to change the names, let's say instead of n I wanted to change that to maybe ny. Then you can always go up here to the formulas tab and there's something called the Name Manager. And we can go into here and we can edit the value. So I can select on n and we can edit that and maybe now you want to change that to ny for the number of years. Alternatively maybe you messed up the cell reference here and you can change the cell reference that ny is referring to. And then we can click OK and then we can click OK, we can click Close down here. So that's how you can edit values. I'm going to actually change this back to n and we go to the name manager, and I'm going to delete the names. You can hold down the Shift key and click on the last one, and I'm just going to delete these. And I'm going to close, I wanted to show you how we can define multiple variables all at once. So if you've got them kind of in columns here or different rows for the variables, you can highlight all of those and then I can go up here to the formulas tab, create from selection and it'll automatically detect the namesin the left of the values. And so most times you can just press OK and when we do that, you see that if I click on this cell in the name box that's been named P. This has been named i and this has been named n. Now there are some names that you cannot use. Let's say I had R and and I wanted to name this R. If you go up here and you try to name that R, it actually highlights the entire row, so R in Excel is already reserved for rows. You can't name something R, there are other stipulations on variables that you cannot use as names. But if you have an R oftentimes I like to call that R_ or RR, but you cannot use R so I'm going to name that R_. By the way earlier when I changed this name, it automatically updated that formula to ny, but then I changed it back to n and it didn't change back. So I'm just going to delete that and convert that back to n. Another quite valuable tool, you can hit the F3 button. This brings up a Paste Name box that has all of the different variables that you have defined. So these are all the named variables so far. Names are not limited to single cells. Here I've got just a data table, a bunch of different mammals with their mass and something related to exercise physiology known as VO2 max. And I can highlight this entire thing and I can name this data. So if I wanted to I could use data, and in fact I might use that in something like the VLOOKUP function, which you'll learn about in week two of the course. And you can always go back up here. Maybe I didn't want to include that top row in my name data so I can edit that, and I can instead of B2 I can change that to B3. I can edit that and click OK then Close, and if I wanted to see what that referred to you can always type data up here and it shows you the highlighted area for that variable. So hopefully you learned a bit about using names and the name manager and naming cell ranges in this screencast. Thanks for watching.