Question: what number is in between 50 and 55?
Answer: When you ask "What number is halfway between 50 and 55?" we assume you mean the number in the exact middle of the two numbers on a number line, as illustrated below, where X=50 and Y=55. Thus, the number halfway between 50 and 55 is 52.5. As you can see, the halfway number is 2.5 higher than 50 and 2.5 lower than 55.