 For this example, we have an IO device that listens to addresses around BCDUDAD. But its decoder is going to ignore lines seven and eight. So it will actually listen to more than just this one address. It will actually be able to listen to several different addresses. And thus, it can also implement multiple different operations. So if we're interested in exactly which address is this device can listen to, we'll need to figure out which ones are line seven and eight. Since we normally count bits starting from the least significant and moving to the most significant, the very rightmost bit in that rightmost D is bit zero. So bit three is the leftmost bit of that rightmost D. Then we're starting to get into that A. So line seven will correspond to the leftmost bit of the A, the most significant bit there. And line eight in turn corresponds to the least significant bit of that second D. So all of the addresses that this device will listen to will be required to have the same 30 bits except for bits seven and eight. So I'm going to begin by just writing down four copies of those 30 bits. So I have two hexadecimal digits in here that I haven't specified yet. I have the most significant bit out of this hexadecimal digit and the least significant bit out of this hexadecimal digit that I still need to work out. Since each of those bits can be either a zero or one, I'm going to have two different possible options for each of these spots. So I can either have an A here or I can have whatever the A is with the eight bit turned off. A is ten, so if we ignore the eight bit, we would still be interested in the two bit and having the one and the four bits turned off. For the D, we're interested in the least significant bit. So as a D, that least significant bit is already a one. So I'll go ahead and put D's in here. And you can notice I've got my BC doodad back. And if I take the one bit from the D and I turn it off, then it's going to be a C. So D minus one is C. So these other two have C's in them. So these are the four different addresses that this device can listen on. And as you'd expect, it does include the BC doodad, but it includes three other addresses that are slightly different. They each differ in those two bits. It's seven and eight.