Comparing Absolute Values: Is -|-123| Equal to |+123|?

The opposite of a number is what you add to a number to get zero. The opposite of a positive number is a negative number. And the opposite of a negative number is a positive number.

For instance, the opposite of the number $123$ is $-123$.

In this question, we are asked about $-\left|-123\right|$ and $\left|+123\right|$.

The absolute value of any number, whether positive or negative, is its distance from zero on the number line, without considering the direction. Thus, $\left|+123\right| = 123$ and $\left|-123\right| = 123$.

Therefore, $-\left|-123\right| = -123$ and $+\left|123\right| = 123$.

Since $-123$ is indeed the opposite of $+123$, the correct answer is Yes.