Let the two numbers be \( x \) and \( y \). According to the problem, the distance between the two numbers on a number line is represented mathematically as:
\[ |x - y| = d \]
where \( d \) is the distance between the two numbers. Additionally, we are given that the sum of the two numbers is zero:
\[ x + y = 0 \]
From the equation \( x + y = 0 \), we can express one number in terms of the other. Let's express \( y \) in terms of \( x \):
\[ y = -x \]
Now, substituting \( y = -x \) into the distance equation, we have:
\[ |x - (-x)| = d \] \[ |x + x| = d \] \[ |2x| = d \]
This simplifies to:
\[ 2|x| = d \]
From here, we can solve for \( |x| \):
\[ |x| = \frac{d}{2} \]
This gives us two possibilities for \( x \):
- \( x = \frac{d}{2} \)
- \( x = -\frac{d}{2} \)
Now, we can find \( y \) using \( y = -x \):
- If \( x = \frac{d}{2} \), then \( y = -\frac{d}{2} \).
- If \( x = -\frac{d}{2} \), then \( y = \frac{d}{2} \).
In both cases, the two numbers are:
\[ \left(\frac{d}{2}, -\frac{d}{2}\right) \quad \text{or} \quad \left(-\frac{d}{2}, \frac{d}{2}\right) \]
Thus, the two numbers are \( \frac{d}{2} \) and \( -\frac{d}{2} \).