4. Which expression represents the following calculation? Add 16 to the quotient of 72 and 8. ​

72+8=80+16=96
So the quotient means the problem.(addition, subtracting etc)

The first one, i believe, would be correct. all the others have one thing in common, and that's that they have repeating numbers. in the second one, x and y have repeating 6's and 3's, and in the third, x and y have repeating 6's as well. in the last one, there are repeating 3's. the first one has no repeating numbers.