 So let's do an example of a series circuit solving for everything in the circuit. Now if you haven't already watched the strategy video that explains how this all sets up, you may want to go back and watch that. I'm going to go through this kind of quickly just to give you a basic idea of what you would do. And one of the very common circuits you may see is one where they give you the two resistances and the voltage of the battery. If it's in a series circuit, then you'd go ahead and put your individual resistances for the R1 and the R2 and then the batteries voltage will go down on the equivalent one. Now in this particular case, you would take your numbers for the resistance 1 and resistance 2 and you'd add those up to find the equivalent resistance. So in this particular case, that's going to give you 6.0. And that's got a unit of ohms. Now in order to find your value over here, because again, looking at the table, whenever you've got a row or column that only has one unknown, you're going to be able to solve for that. And to follow in the current, you're going to take the voltage and divide it by the resistance. So if you take 9 and divide it by 6, you get 1.5 and that's going to give you amps. Now at this point, we come down to this relationship that once you've got the current for any one part of the circuit, in series, all of them are going to be the same value. So we can plug it in in both of the other spots. Once you've got those values in, you'll notice that both the top row and the middle row only have one unknown thing here. And so you can come back over here and actually work through to find the voltages. And again, the voltage is going to be the current times the resistance. So in this particular case, you take your 4 ohms times your 1.5 amps and you get 6.0 volts. Then for this row, you'd have two ohms times your 1.5 amps, which is going to give you 3.0 volts. And as a last check, it needs to fit this last column condition, which is that the voltage over resistor one plus the voltage over resistor two should add up to give us our equivalent resistance, which in this case it does. Now these were really nice numbers that I had picked out ahead of time, just to make it work out a little bit easier. Don't be surprised if you end up having decimals or fractions that aren't so nice. I suggest for my class that you work it in decimals, but you always keep at least three or four significant digits so that you don't end up with rounding errors in the end. Now let's take a look at one more example here, but an example where you don't have quite the same set of information starting. So let's say I knew one of the resistors, but not both of them. I knew one of the voltages, but not both of them. And one of the currents. As long as we've got information distributed here across the columns and rows, then I should be able to solve the circuit. And again, you have to know if this is series or parallel. This is a series example. Now initially, it looks like you don't have enough information do much on this circuit because I only have one thing in each row in each column. But remember that because it's a series circuit, all three of these columns have to have the same value for the current. So if I plug in that two amps on each one of these, now I see that my top row has two values with one unknown. My middle row has two values with one unknown. So in this case, I'm solving for the voltage on the top row, which would be the current times the resistance, our two amps times our four ohms and two times four is going to give me eight volts. On the second row, I'm solving for the resistance and it's the voltage over the current. So if I've got 10 volts divided by two amps, that's going to give me 5.0 ohms. Now I've got some choices at this point because I could either solve for the voltages, which have to add up. Eight plus 10 is going to give me 18. And I can also add up my resistances because in series, they just add up. So four ohms plus five ohms is going to give me nine ohms. But I also want to double check and make sure now that my bottom row fits ohms law. And if I've got two amps times nine ohms, sure enough that gives me 18 volts. So everything checks out here. When you finish your table, you want to make sure that each row follows ohms law and that each column fits the series rules. So those are two examples for how you could solve a simple series circuit and find all of the resistances, voltages and currents for that circuit.