What is the absolute value of -15?

The absolute value of a number is defined as its distance from zero on the number line, regardless of direction. This concept means that absolute values are always non-negative.

For the number -15, its distance from zero is 15 units. Therefore, the absolute value of -15 is 15, which reflects how far it is from zero without considering the negative sign. This is why the correct answer is 15. It effectively conveys that distance is always a positive measure, aligning with the definition of absolute value.