Sonji plots –9 on a number line to represent the depth of her sailboat underwater and labels it B. She plots positive 20 on the same number line to represent the height of her sailboat above water and labels it A. Sonji asks if B, the elevation below sea level, acts as an opposite to A, the elevation above sea level. What is the best answer to her question?

Question

Sonji plots –9 on a number line to represent the depth of her sailboat underwater and labels it B. She plots positive 20 on the same number line to represent the height of her sailboat above water and labels it A. Sonji asks if B, the elevation below sea level, acts as an opposite to A, the elevation above sea level. What is the best answer to her question?
Although they are on opposite sides of sea level, they are not opposites since –9 and 20 are unequal distances from 0.
Because they are on opposite sides of sea level, they are considered be opposites.
Because they are not on opposite sides of zero on the number line, they are not opposites.
Although they are on opposite sides of 0 on the number line, the reason they are considered opposites is because they are the same distance from sea level.

GPT-4o mini · Answer

The best answer to Sonji's question is:

Although they are on opposite sides of sea level, they are not opposites since –9 and 20 are unequal distances from 0.

This explanation accurately highlights that while the numbers –9 and 20 are positioned on opposite sides of sea level (0), they are not considered opposite values in the mathematical sense because they do not have the same magnitude or distance from 0. In this context, opposites would imply equality in distance from a reference point, which they do not share.