 Okay, so the last one asks us to convert 4 ounces to kilograms, okay? So, let's write down what the problem gives us. We want to go from ounces to kilograms, so we got, well, it's 4.00 ounces. But if we look at our conversion factors, we don't have a conversion factor that goes directly from ounces to kilograms. But we do have one that goes from ounces to pounds, and we got one that goes from pounds to kilograms. So, in fact, this is the cool thing about conversion factors is you can use as many as you need. Okay, so if we look at our conversion factor from ounces to pounds, 16 ounces is one pound, okay? And pounds to kilograms, it's 2.2 pounds equals one kilogram. So, you just use those two conversion factors in succession to cancel out your ounces and get kilograms. So, remember, we've got to get rid of our ounces, so we've got to put the ounces on the bottom. So, it's 16 ounces per one pound, but we don't want pounds either. We want kilograms, right, because we're going from ounces to kilograms. So, we've got to get rid of pounds by putting them on the bottom, and kilograms we want. So, we'll put them on the top. It's one kilogram for every 2.2 pounds. And then, just get out your calculator, and let's see, just to make sure. So, ounces over ounces, that cancels pounds over pounds, cancels, and we're left with just kilograms. Remember, we only use the significant figures in the number that's given to us, and that's three, two, two. We don't even worry about that, one, one. We don't even worry about those conversion factors. So, three sig figs, so we say four divided by 16, and then divide that by 2.2. And we want to take this to three sig figs, so zero point. I wanted to do it in scientific notation, which we'll do in a second. One, one. So, we've got to, so one, one, three, six kilograms. That's not three significant figures, right? So, we've got to round up, because six is higher than five, so zero point one, one, four kilograms. And if we wanted to, we could take that and put it into scientific notation. One point one, four times ten to the negative one, kilograms. So, that's how many kilograms are in four ounces, less than one. So, remember when you don't have a conversion factor that goes straight from one to another, you do have one that's an intermediary, you've got to do the kind of step, step. So, just remember all that, and you should be fine.