Which of these could you measure with a ruler? A. the volume of water in a cup
B. the volume of cream in a cup of coffee
C. the length of a textbook
D. the weight of a watermelon

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.

1.) 18+5 is one way i’m pretty sure there are others but i can’t think of them right now