Question

Why are 2.15 and -2.15 are opposites

Answer 1

The opposite of a positive number is a negative number.

Example: The opposite of 5 is -5.

The opposite of a negative number is a positive number.

Example; The opposite of -5 is 5.

So the opposite of 2.15 is -2.15 and the opposite of -2.15 is 2.15.