The Goal Seek tool allows you to calculate the value of an input, based on a defined value of an output. So, in our example here, what we want to do is work out what discount rate we need in order to have a net present value of zero. So, first thing's first, the shortcut is ALT + AWG. That will bring up the Goal Seek box. And what we want to do is set cell C21, which in this case is the net present value cell. We want to set that to a value of zero. Okay? So we're gonna set that to zero, and we're gonna set it to zero by changing the value in cell C15. And C15 is the input cell that drives the set cell, and in our case, that's the discount rate.