The distance between -18 and 15 is equal to
15 - (-18)
15 - 18
18 - 15
-18 - 15

Hey, there! 

The word "distance" means "subtract:" 

For A: The question isn't asking the distance of & (So, this cannot be your answer)  (it would give you the result of  )

For B: The question isn't asking the distance of & (so this isn't answer) (it would give you a result  )

For C: It's not asking for the distance of   and  because it would give you the outcome of a  (so, this isn't your answer) 

For D. it is doing what the question is asking so this would most likely be your answer. The answer would be (if we solved it) 

 

Remember to break down the words (or numbers) it will come in handy for the future

Good luck on your assignment and enjoy your day!

                                       ~