 In this video, we're going to do some examples of unit conversions. Before we actually get to the example problems itself, I just want to remind you of some algebra rules that are necessary here. First of all, if I have two quantities that are equal to each other, like A equals B, then I can divide one by the other, and A over B is equal to one, and B over A is equal to one. Along with this rule, we have the fact that if I take any number and multiply it by one, I have the same number. I haven't really changed it. Now where this comes into play is where we start having our conversion factors. And I'm going to start with a conversion factor that you're probably very familiar with. One foot equals 12 inches. So the one foot is our A, the 12 inches is our B. So that means that one foot over 12 inches is equal to one, or 12 inches over one foot is equal to one. So now we can actually start doing some conversions, and we're going to do this in both directions. So let's start, and let's say we have something like 2.5 feet, 2.5 feet. And I want to convert that into inches. What I need to do here is I need to sort of set up a fraction where I'm going to be multiplying this 2.5 times one. Now we have to choose between A over B or B over A. Because I'm trying to get rid of the feet, I want the feet part to go on the bottom. So that's our one foot factor. And then our 12 inches goes up on the top. So what I have to start with, I need to put my conversion factor on the opposite side of this fraction from what this has. Now when I do that, I can cross off the feet because they cancel each other out. And I'm left with 2.5 times 12 inches over one. Now I have a little calculator open over here. And we can type in 2.5 times 12 and divided by one. And that tells me that it's equal to 30 inches. So my answer here is 30 inches. Now what I've really done is looking at this problem. I've said that 2.5 feet is equivalent to 30 inches. And I converted the feet into the inches. Now we can do the same thing in the other direction. Let's say instead of starting with feet, I started with something like 93.5 inches. I again want to set up a fraction. But in this case, I want to have the inches part down here on the bottom and the foot up on top. And what that's going to do is that means the inches are going to cancel each other out. But I'll be left with feet. So again, I have to take the 93.5 times one divided by 12. So over here in my calculator, if I do a 93.5 times one divided by 12, that's going to tell me my final answer is 7.7 917 feet. Now later in my class, I show my students how to actually round things off to a acceptable level. But for right now, I can go ahead and put that in there. The calculator actually gave me more digits, but it rounded it off just a little bit. So I can put that number down here. So I went from inches into feet by using this conversion factor. So whatever unit you have on the top, you want to put the conversion vector for that one on the bottom. Now, these problems here can get more complicated. So I'm going to separate this into two videos, and we're going to call this unit conversion part one.