What it means is you add them all together then you divide by how many numbers are there. The answer is 6 because 8+6+4=18 then you divide 18 by 3 and get 6.
678 is what you have left but if you would put it as a fraction of what you have left now it would be 678/1012... which then take and put it as a decimal which is a form of a mixed number = .6699
