 I'm going to watch it over and over again. Yeah, so let's record it then. So this one says, a penicillin derivative is used to treat infections with an adult 24-hour dosage of 35 milligrams per kilogram of body mass. This is to be given in three injections daily. So this antibiotic is prepared by the pharmacy in solution form with a concentration of 130 milligrams per 5.0 milligrams. What volume in milliliter should be given in each injection to an adult with a mass of 12.5 kilograms? So the first thing you want to do is get rid of some of these conversion factors. All of these are unit conversions. They've been turned to conversion factors for you. The first thing I really like to do is make these into something that's a little more manageable for me. Because remember how we like to put this, then multiply it by this, then this, and this. So we're going to do it in stepwise fashion like that. So well, we've got all this information. So we want to get the number of milliliters eventually. So let's go ahead and write these differently. So this one says the dosage is 35 milligrams per one kilogram of body weight. So this is kilograms of body weight there. So if we use those, we can already get milligrams from that. And then here, this is just a ratio written kind of weird, like text message way, all in one line. So how are we going to write it at 0.0 milliliters like that? So hopefully that helps you already. And remember, with these ratios, we can flip them this way or this way. They mean the same thing. So let's go about figuring out how many milliliters in all three injections. So remember, there's three injections for a 24-hour period. So let's do all three injections. So let's not worry about this number yet. So the volume in a 24-hour period is going to be, well, we want volume units. So the only volume units that we have in here is 5.0 milliliters. Does that make sense? So that has to be on the top. If that's on the top, then we're going to have to flip this thing over. So it's going to be 5.0 mills divided by 130 milligrams of the drug. Does that make sense? So we've done so far? OK, wonderful. So now we're going to multiply that by something else. Well, we want to cancel out milligrams, right? Is there anything up here that has milligrams in it? The top one up there, right? And we want the milligrams to be up here. So we're just going to write it how it is here. One milligram, or, sorry, 35 milligrams per one kilogram of body weight, OK? So 35 milligrams. And this is of the drug for one kilogram of body weight. And I put that body weight there, so milligrams and kilograms wouldn't be confused, OK? So now look what I can do. Milligrams cancels out with milligrams, OK? So now I have milligrams milliliters per kilogram of body weight. But I know how much the guy weighs, the adult weighs, right? 12.5. So I can multiply that by 12.5 kilograms like that, body weight, and that cancels like that, right? So what does that mean? So the volume in a 24-hour period is going to be whatever this expression comes out to. And I didn't bring my calculator. And do you mind if I use your calculator? That's terrible. OK. So the way I do it is 5 times 35, and then times 12.5, and then divide that by 1.30, yes, OK? And so to two significant figures, unfortunately, well, we'll just go out for right now, and then we'll do the two significant figures in a little bit, OK? Not that it won't matter, but we'll just say 16.8 milliliters. So that's milliliters per one injection, remember, OK? So that's, or per 24, per three injections, OK? Per three injections. Because that's for every 24-hour period, per three injections, OK? So this is 16 mills per, if you want to say, 24-hour period. And then multiply by this ratio here, right? So we got 24-hour period divided by three injections. So this will give us the volume per injection. Does that make sense? Because we're going to cancel out like that, OK? Does that make sense? Because it's like magic, right? It's awesome, huh? OK, so now we don't have to worry about 24. So we're just going to take that and divide it by three. And so each one of the injections to two significant figures, so it's better that we do it this way, is going to be 5.6 milliliters. And I think that's the right answer, right? Yes. OK, wonderful. So that was a good question. Are there any questions on this one?