We are going to take-a-look at our first function those predefined calculations that are built inside of a cell.

The first one that we are going to take-a-look at cell B8 is the **SUM function**. This is the most common most widely used function in all of Excel worldwide.

Let open file : Mothly Budget

Now I am back inside of our example file this is that monthly budget that we have built up to this point.

We start out which is some basic arithmetic style calculations.

Now you select cell B8 then hit **F2** on the keyboard.

If do not hit **F2** you also see it Formular on the Function bar.

We only had one two three four records there (B4, B5, B6, B7).

So doing this plus this plus this plus this wasn’t too bad although I know you do not want to do a lot of it. What if you had 20 30 50 hundreds or thousands of records. It is not really something you want to do. You want to retype that over and over again, No way no way.

Unless I am getting paid to do it by line item, Maybe I will do it but probably not.

I want to find a quicker more efficient way of doing this. And this is where a function something like the some function will come in and make this so much more efficient faster it is huge.

Let us take-a-look at the sum function. hit Escape key just to close editing cell.

To start this out we are actually going to replace all of these formulas.

Now to start this out we are actually going to replace all of these formulas, Let’s delete those out. So from E4 to E8, from B8 to D8

Now that broke the percent calculation, not too big of a deal, It just means this pound did slash zero exclamation Mark error, this is your divide by zero error and mathematically you cannot divide by zero, because we have no numbers there, It is given us that error.

No problem, It will come back but we just got to fill out the calculations now.

The process that we are about to go through here might be just a little bit different based on the version of Excel that you are working with. if you are on the brand new version there may be a little bit of automation happening for you, you might see a little bit difference but nothing huge.

I am inside B8 and I just want to sum up this range of cells B4 to B7.

The first time, we use this one we are going to go through the formulas tab and we are going to go find the SUM function.

Some of you watching this might be familiar with the shortcut that you could use it, or even a keyboard shortcut one button press that would do all this for you.

Now if you are familiar with the shortcut you are familiar with auto SUM, We are building some key blocks here some key building blocks, That is going to help us as we get into more and more advanced topics.

So I am in B8, I am going to go to my formulas tab instead of there we have got this function library, the function library contains all these books and this might be a little bit different compared to the earlier versions, the buttons just look a little different, but for the most part it is the same thing.

I am going to go to math and trig, Math and trig I mean to go ahead click on there, you are going to get a list of all these math related built in functions memory predefined functions, that are going to do the calculations for you based on input arguments that we give it.

I am going to find SUM, I will give that a click.

This is going to open up the function arguments window that we saw in the prior lecture.

Here is where it might be a little bit different compared to the earlier versions depending on what you are using.

B4:B7 done, I can see the result right there is right there formula result and I have done I could just hit OK.

Again Excel is pretty smart and they continually improve it with each new iteration Excel gets better and better and it gets smarter and smarter, pretty soon Excel is going to take over the world, it is to be able to do so much force it just automates the experience well if you are on an earlier version.

You may not have gotten the default range of cells in there so I am just going to delete them out of. I got rid of what is a number one before through be a gone, what I am going to do is I could type it in and you say I want B4:B7, I can do that or let us leave that out, again I can just select the range of cells that I want I want B4 to B7 then hit OK.

I used the built in function sum to sum up arrange yourselves. No more work for me now I want you to practice this, I want you to go through and complete it for February.

Remember here, I am a set up before you go to formulas math and trig you will find the SUM function

I do it similar for cell E4

The rest of the calculations get all your sums, then we are going to take-a-look at a few other functions, these predefined calculations to do some more math.