If a memory cell whose address is 5 contains the value 8, what is the difference between writing the value 5 into cell number 6 and moving the contents of cell number 5 into cell number 6?

There's a distinction between the address of the cell and the value it contains, and the difference in this problem lies in that distinction. The contents of cell 5 are the value 8, so moving that to cell number 6 would set its value to 8 as well, which is clearly different from the value 5.