 OK, guys, let's try to figure out the oxidation numbers of, well, effectively, the chlorines in these two compounds. The top one's perchloric acid, and the bottom one's hypochlorous acid. So what do we know already about the top one, of course, or both of them? So it's going to be neutral. So the whole thing is going to be equal to 0. These oxygens, oxidation states are negative 2. And how many do we have, or four of them? Cl is what we're looking for. So it's going to be an x, and there's only one of them. And then h, if you guys remember what that is, plus 1. So let's go ahead and figure this out. So we've got 1 plus x minus 8 equals 0. So x minus 7 equals 0. So oxidation number of chlorine in this case is plus 7. Do you see that? OK, so let's do this one now. So the whole thing is 0, right? Oxygen is minus 2. There's one of them. Plus x, there's one of them. Plus a plus 1. Is everybody OK with what I've done there? So we've got 1 plus x minus 2 equals 0. So x minus 1 equals 0. So x equals plus 1. So chlorine in this case, oxidation number is plus 1. So chlorine can have weird oxidation numbers, OK? So just like a lot of those, especially the bigger non-metals, like phosphorus, sulfur, bromine, we'll see some of those later when we talk about expanded babes, OK? So let's talk about this problem here. So are there any more questions on this particular problem? So we can do that problem in a second. Does everybody understand this one? Yeah.