A dolphin is at the surface of the ocean. What is the dolphin’s elevation? The dolphin dives 20 feet below the surface of the ocean. What is its new elevation?

No because if you do the higher number minus the lower number you will get a positive. if you do it the other way around you will get a negative number

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.