 Now, let's look at the first one of the extra circuits that are the complex ones. And we're going to use this as an example to show you kind of what you're expected to do. So in this particular circuit, I've got one battery over here and I've got one, two, three, four, five resistors, although some of them are labeled A, B, C, and then the other one's four, five. And it has the particular resistances labeled next to the resistors as well. If I was wanting to find the equivalent resistance in this circuit, again, I want to identify subparts of the circuit that are either in series or in parallel. Now, one of the ways that you can do that is by first focusing on where is there actually a junction? And a junction is where multiple wires meet. Now, A is not a junction, even though it looks like I've got one wire in and one wire out, because it's really kind of a corner. But down here, I've got a junction, because one wire then splits into two. And down here, I've got a junction because the two wires come back together. Now, you see a split and come back together and you might start thinking about parallel, but let's look at what's happening on those branches to start with. So if I go from one junction point along these wires, I see that both of these are on the same branch. Now, this isn't a junction, again, it's a corner. So Rb and R4 are together on a single part of the circuit. And similarly, on this side, Rc and R5 are on a single branch of the circuit. So what that means is that these two sections are each series sections. Now, I could pull out my calculator here, but you should be able to see very quickly that if I combine 2 ohms and 18 ohms in series, well, in series, they just add. And 2 plus 18, you should be able to do it in your head, that's 20. So I really have a 20 ohm resistor on this branch. And again, you can do it in the calculator, but I'm saving these for later, even though you can probably do it in your head. 3 plus 12, not times, plus 12 is going to give me 15. And so over here on this side, I've got 15 ohms. So now I've got a 20 ohm resistor and a 15 ohm resistor if I think about it in terms of the equivalent resistance. Now, depending on how good you are at sort of seeing the shape of these things, you might want to redraw it. I've got a line that comes down here, then I've got another branch and a branch, and they come back together. And over here on this branch, I've got 20. Over here on this branch, I've got my 15. And up here, I still have my original 6. So this is like redrawing the circuit to show the simplified version. Well, now we can see a little bit more carefully that this part of the circuit is in parallel. Now, I don't do these ones so well in my head, so I'm going to have to come over here and do 1 divided by parentheses. Don't forget your parentheses here. 1 divided by 20 plus 1 divided by 15. Close my parentheses. And that's going to give me my equivalent resistance for this part of the circuit over here. Now, notice it doesn't really matter if I draw it vertical or if I switch it. So I'm going to go ahead and now switch it so that over here, I've got my 6 ohm resistor. And then I continue to what is now my new combination of the 20 and 15, which is going to be approximately 8.57. And fill that in as my 8.57. And what I see is that that whole thing now, the 6 and the 8.57, is an example of something, which is now in series. So how do I combine them in series? Well, I'm just going to add them together. So I'm going to have 6 plus 8.57. And that tells me that my equivalent for the entire circuit is a grand total of 14.57. So I've identified where my junction points are, saw that I've got some series sections, did those first, then see that those two series sections are in parallel. And when I replaced that, the remaining two were in series, giving me my final answer for the circuit of 14.57 ohms.