 Alright, well what about subtraction in non-standard bases? So, here's a nice problem for a non-standard base, we have a, we want to cut off a 3 foot 9 inch board, half of a board that has a length of 8 feet, and we want to figure out how much is left. And again, because we have a somewhat non-standard base, we do need the conversion factor 12 inches is equal to 1 foot. So, we'll go ahead and set up our place value chart with our operands. So, I have 8 feet, that's my original board length, and I want to subtract from that a board of 3 feet 9 inches. Now, if I want to prepare this to do the subtraction in one shot, I want to look at our numbers here. I want to subtract 3 from 8, well that's not a problem, but I also need to subtract 9 from 0, and I can't do that. So, in order to prepare this subtraction, what I'm going to do is I'm going to split the 8 feet into a 1 and 7, and I'll trade the 1 foot for 12 inches. So, there I have my subtraction set up, and now I can do both subtractions. 3 from 7, 9 from 12. So, I'll subtract. 3 from 7 gives me 4, 9 from 12 gives me 3, and there's my final answer. 8 feet minus 3 foot 9 is going to be 4 feet 3 inches.