 Some of the most useful things you can do in a spreadsheet are also the most basic. And so I want to show you some of the most important formulas that you'll use most often to get the first steps of insight out of your data. The three that I want to show you with one variation on them are count and sum and mean. A count is used to simply decide how many values you have in front of you. It's getting your sample size. And what I'm going to do is I'm going to take this series of dates here. And I've imagined like we have a yoga studio and we've got the number of people attending a group class on each day. Now please note one of these is not a number it's text I wrote down because the fourth of July is a holiday in the US. But let's do this first one, which is count. Now, I can do this two different ways I can type equals and then the word count. But because this is one of the basic formulas, there's a shortcut to it. If I come right up here, this is a Greek Sigma that's the summation sign. If I simply say count, it inserts equals count and then the parentheses and it simply wants to know what data should it count. And I'm going to drag, click and drag over these numbers. And when I hit return, I get 13. So there are 13 numbers here. The thing to remember about count is it only counts how many numbers there are so it ignored this piece of text. On the other hand, there may be situations where you need to include even written things you need to include any kind of information that's in a cell. And in that case, you're going to want to use a small variation called count a, you can think of count a as count all not just numbers but everything. And this one I am going to type out I'm going to put equals. And then I'm going to type in count a, and that pops up right there so I can click on that. And then I'm going to click and drag over the data. And then I'm going to put a closing parenthesis and hit return. And that tells us that there are 14 values within this range of data. There are 13 numbers within that range. But there are 14 values 14 cells that have something in them. So counting can be very important just for counting how many entries you have. Even more useful is going to be adding things up some. And something's really easy to do. I'm going to put my cursor right here select that cell, and I'm going to come back up and hit some. And it simply wants to know what data to add up. So I'm going to click and drag over these. And I have a sum of 170 so over 14 days we had 13 classes at the yoga studio and we had a total of 170 people show up, which raises the next question. If we had 170 people show up over 13 classes. What's the average number of people per class. Now there's two ways to do this. One is to simply take this sum and divide it by the count. That is the definition of a mean. But I can also use the built in formula for a mean, which is nice because it's going to ignore, for instance, that piece of text in there as well. So I'm simply going to have this cell. Come over here and click average. The average in the mean in most situations refer to the same thing. It's where you get a total of the number of people with the amount of money, the amount of time and you divide it by the number of cases you're distributing across. I'm going to hit average. And then simply drag over these numbers, hit return. And that tells me that I have an average of 13.1 people in each class period. Obviously, sometimes it's higher, sometimes it's lower, we go from seven to 21. But an average of 13. And so these are very simple operations, simply counting how many numbers you have, adding them up and getting the average. But you're also going to find those are going to give you an enormous amount of insight. The simple operations are most often the most effective in getting meaning out of your data. And these simple arithmetic procedures are very simple to do with the built in functions in Google Sheets.