Suzi starts her hike at 210 feet below sea level. when she reaches the end of the hike, she is still below sea level at - 107 feet. what was the change in elevation from the beginning of suzi's hike to the end of the hike?

Suzi starts out her trek below sea level at an elevation of - 210ft. You know this because the question reads below sea level. When she gets to the end of her hike she is still below sea level at - 107ft. We can use simple math by subtracting 107 from 210 to figure that she has traveled a 103ft up in elevation. She is still below sea level so we still see the noted elevation as a negative number.