Excel basic formulas with cell references

okay in this video now we're going to start doing math in uh in an Excel spreadsheet using the actual numbers that are already on the spreadsheet so one thing that we can do right away is add up a to a column total uh this is something that is going to happen all the time so I'm going to click on Cell C12 and obviously I like to get the total of that column well doing a column total or doing a rad total is such a common feature that uh Excel makes it very easy for you to do that follow my mouse up here uh this guy over here is called an auto sum you're just going to click on that and then usually it guesses properly what you want to do in fact in this case it did look what it says it says equals sum so it's going to add up everything between C4 uh and C11 uh now this is actually a special formula that's called a function there's a lot of built-in functions which we'll talk about uh in this video and other videos but anytime that you have a a function you're going to have uh the parameters within parentheses uh so basically this is saying add up or sum everything between C4 through C11 when you see that colon there that means it's going to be a range of cells and the way you would read that is C4 through C11 I want to hit the Anar key and now it adds up that column of of uh data so that's a really quick way to do a sum watch again I'm going to uh click on that cell and actually delete it all I'm really going to do is click on the auto sum and then hit the enter key and then you can see it has that column total now what's nice about these formulas is that if any of the numbers change in that column then the total will recalculate so I'm going to change this to 6000 and then watch the total at the bottom and there's how that recalculated so um the the auto sum can do a column total and a row total or it could just add up a range of cells in general now let's come over here to February let's just say that February is going to be be the the January number plus $300 so one way to do that if you looked at uh the the the video on basic math uh I would say equals 6,000 + 300 and that would certainly do what we want to do I'm going to hit the enter key and you can see the result is 6,300 but if I click onto that sell you you can see the formula says equal 6,000 + 3 300 and that's fine uh if you uh need to know how to do that basic uh type of formula go back to one of our videos that that's called basic math but really here's the way most people are going to do these formulas I'm going to delete this uh in our spreadsheet you see the number 6000 is already in cell C4 so in my formula I'm just going to uh use the value C4 and then that'll pick up the number that's in cell C4 so in this case I'm going to type in the equal sign uh all form I'm going to start with the equal sign now I can either click on Cell C4 or I can even use my keyboard arrows to point to that or I could I could have just typed in C4 there uh so what this means is I'm I'm building the formul that's in D4 but I'm using the cell C4 in that formula and I'm just going to say plus 300 so instead of saying equals 6,000 + 300 I'm going to say equals C4 + 300 and what that means is take take the number that's already in C4 and add $300 I'm going to hit the enter key and it gives us the same mathematical result but here's why we did that I'm going to go over to cell C4 and I'm going to type in 7100 there now watch D4 notice how D4 changed the reason that D4 updated is because the formula in D4 looks at cell C4 so if C4 changes then therefore for D4 will also update so that's really the better way to do your formulas if if the number that you're looking for is already on your spreadsheet somewhere then you're going to include that cell reference within your formula so uh let's try that again let's say maybe the purchase Department went down by $400 so I'm going to say equals um now I'm going to click on Cell C5 and say minus uh 400 and we'll H the enter keate so now if CI changes let's let's type in 3800 there then notice how D5 also updates so let's take a look at those formulas you're going to click on on that cell notice up here on the formula bar it shows you the actual formula so that's where you can change that uh but the the spreadsheet shows the result of the formula all right but notice how all the formulas always start with an equal sign then I conclud include the cell references and then uh if you look at the formula for the basic or if you look at the video for the basic math uh you know this formula can be longer than than just uh one mathematical operation you can make that as long as you wanted to and then that's that's when you would start using the parentheses to group your numbers together so uh I'm actually going to delete these now let's say I want to take those two cells and add them together I'm going to say equals uh I'm going to click on C4 and I'm going to add it to C5 right so I can use more than one cell in the same formula let's say we're even going to subtract I'm going to hit the minus sign and let's say we're going to subtract C6 this can go on as long as you want it to I'm going to hit the nrk and it it gives us a results there now uh when I click on that cell you see it includes C4 C5 and C6 if any one of those numbers should change then D4 is going to update because D4 refers to uh those three cells all right so that's how you're going to build a a a basic formula here in Excel but let's take that a little bit further so let's let's go back to our original example I'm going to hit my delete key so I can delete that cell let's go back to uh equals C4 plus 300 and you can see of course it took the uh C4 and and added $300 to that