One of Excel's strengths is its hundreds if not thousands of different functions that you can use. So in this screencast, I'm just going to kind of give you a real basic introduction and overview of functions and how to use them in Excel. Excel functions always start with an equal sign. So you would plug this into a cell on the Excel worksheet. So it has a function name and then you have arguments that go in parentheses. So this is just a real generic representation of how to use functions. There are three types of functions in Excel. There are functions with zero arguments, there are functions with one argument, and then there are functions with multiple arguments. Now these arguments always go inside the parentheses after the function name. These arguments can be single cells and values so you can reference other cells on the spreadsheet. Or you can just plug in values, so you could take the square root of five for example. And arguments can also be cell ranges, meaning multiple cells. So I'm going to go through a couple examples now that kind of demonstrate these different types of functions that we can use. First of all, let's talk about a couple of functions that have zero arguments. There is a function in Excel called NOW. Even though there aren't any arguments you still have to put empty parentheses. And what that does, it tells you the current day and the time. There's also a TODAY function, same thing, no arguments but you still need to put the parentheses. If you leave off those parentheses, it's just going to give you a name error. So you definitely do need those parentheses on there and it'll tell you today's date. Another one that comes to mind is the PI function. So pi, some of you might recall from geometry that if you look at a circle and you take the ratio of the circumference to the diameter that ends up being this value pi. And pi has a value of 3.14159 dot dot dot dot dot and keeps on going forever. There's a built-in function for pi, you can just type in PI() and we get the value of pi. So these three don't have any arguments. We can also have functions that have a single argument, as an example the square root, so I could do the sqrt(5). Now keep in mind, the arguments can be values and numbers like 5, or I can refer to other areas of the spreadsheet. So other cells, so I can take the square root of cell B4, which is pi. The square root function is a function that acts on a single value or a single cell. We can also have functions that operate on ranges of cells. One example is the MAX function. The argument here, I can click and then I can drag, so I'm left clicking and dragging. And then we put the right parentheses and it looks for the maximum in that range of cells. It doesn't have to be a single column. I could also, in my MAX function, it could be an entire array. So my argument could be F2 down to G7 and it's going to look for the max. There's also a MIN function that does a similar thing. We can also have functions that have multiple arguments, an example of this would be the combin function. This will tell you how many different combinations there are. For example, if you have four different students and you want to put them in pairs, this will tell you how many different combinations there are. So in fact, there are six combinations. Lots of other functions, there's one for you financial and business folks. It's called the future value and this actually has lots of arguments. We have three mandatory arguments and then there's a couple optional arguments. Whenever you type in a functioning see these square brackets those square brackets indicate that those arguments are optional. You certainly should not memorize all these functions. You probably will get to know some of them very well, depending upon what your particular field is. You can always go up here next just left of the formula bar, there's this little insert function button. So if you don't know if there's a formula available you can always click on this and you can search for a function. So for example, if I didn't know what the combin function was, and I wanted to just search for that you can write combinations and click go. And it goes through and there's actually two that are available. There's a minor differences between the two but then it'll tell you how to use that. It'll tell you the formula and then how you can use that and what it does. So I would strongly recommend getting used to this insert function button there. And when you click on that it brings up this box where you can put in the arguments to the function. So that's kind of one way that you can use these functions and it will insert that into the cell on the spreadsheet that you are working with. Alternatively, you can always go up here to the Formulas tab and in the Function Library group, there's all sorts of different functions here. So if you're working with financial you can kind of scroll down, logical functions. And in some subsequent screencast, I'm going to go over some of the more popular functions in each of these categories in more detail. But that's how you can find these functions. And I'm just going to wrap up this screencast by going through kind of just a simple example here. We have cookies, so we have a somebody selling cookies. We have the buyers of the various cookies. We have the cookie type. We have the quantity that the buyer bought from the seller. And then we have the price for each box. In order to calculate Charlie's total sales to Sally we want to multiply 7 by the price. So I'm just going to multiply cell D2 by the price there, and I can press Enter. Now these are in dollars, so let me go ahead and format this to currency, up there, Accounting. And I'm also going to format this column to accounting. And because I wrote that formula as a relative reference, I can go ahead and just drag that down. Or you can double-click down there in the lower right to autofill. That's just using a simple multiplication formula. Maybe we want to have the total sales down here and I could use the sum function. So there's a sum function. This is a function that acts on a range of cells. So it's going to some the entire range there F2 to F12, and I press Enter and we see that our total sales is $197. So maybe want to kind of summarize things down here the total quantity. So this we could use the sum of the entire quantities. So this will tell us the number of boxes. There were 46 boxes sold. Maybe the number of sales, we can count the number of sales. For using non number values you want to use the counta function. So I'm going to count all the items in column A but I'm going to subtract 1 because that top row is just a label. All right, so we've made 11 sales. The maximum sale quantity, so the maximum of this column. So 11 boxes is the maximum number of boxes sold by any one sale. And then we have the maximum sale, which would be the max of the dollars we made from each sale. So that was 38.50 and that's how can kind of make little statistics here. I'll show you about slightly better way to set up tables in some subsequent screencasts. But if you wanted to add somebody on here, then you could always go insert maybe Ella makes another sale to Jimmy, Nutty Butters, 4 of those, $4 each. And it automatically updates that. So Excel is kind of smart like that, if you insert data into your table, it's going to update everything. So hopefully this screencast gave you a better idea on an introduction into to using functions in Excel