 Now let's take a look at using Kirchhoff's current rule where you're not sure the direction of each of the currents and I've got a diagram set up here where I've got a current one coming in a current two coming out and a current three if Current three is going out of the circuit your equation would end up looking like this with the i3 being on the outside of the equation if The current was coming the other direction into the junction then your i3 would be on the left hand side as a current that's coming in Now which one is it going to be? I don't know yet Now there's a few different ways to work with this sort of situation one is to make a guess and use that equation and then depending on when you ultimately get a value for i3 if It's positive the guess was in the correct direction if you get a negative value It must have been in the opposite direction and I want to show you an example of both of those let's say I started out with a value of 5.2 amps for current one and 1.5 amps for current two Well first of all you can make a guess at this point as soon as you know it Which way it probably goes? By noticing that the 5.2 amps is larger than the ones point six five amps Which implies I would need more current on this side of the equation to balance it out Which means it's probably that current three should deserves to be on this side of the equation And so when you set that up you would actually put your current three Going out and you'd use this equation So let's actually plug that in I Would have an equation that would now look like this 5.2 amps coming in 1.5 1.65 going out plus the i3 is on the outside and When I solve that I'd get a value which was 3.55 amps so again my guess which made sense worked But let's just say I went ahead and used this other equation and I assume that the current was going in the opposite direction So I assume that the current was going in To the circuit well, then I would need to use this version of the equation Which means that I would actually flip my one point or my not my one point my current three over to the right-hand side of the equation if I solve that version of the equation I Would have to subtract the 5.2 over to the other side and I would actually get an answer here Which would be a negative value So when I assumed that the current three was on the left-hand side of the equation as something coming out I Got positive 3.55 amps meaning it was going out If I had assumed that my current three would be over on the right-hand side of the equation as one coming in When I numerically solved it. I got a minus 3.55 amps The current three still has a value of 3.55 amps But here the minus sign meant that it wasn't going in it was actually the opposite direction so that minus current means Use the other direction But I could solve my problem. I don't know if I got this one I would not have to go back and rearrange everything in order to get the right answer I could use this as an understanding to get the correct value for the current and Then to know that it's really the opposite direction of what I've chosen there So when you're using Kirchhoff's current rules, there are sometimes where you have to initially take a guess at the direction But when you ultimately solve the math that lets you know whether it was the correct direction Or whether it was the incorrect direction If you have any questions on this let me know