The question asks which value can be added to the number indicated on the number line to sum to 0.

On the number line, the red dot is positioned at $4.5$. To find a number that will sum to 0 when added to $4.5$, we need to find the additive inverse of $4.5$, which is $-4.5$.

Now, let's examine the options:

• A. 4.5 – Adding $4.5 + 4.5 = 9$, not zero.
• B. -9.0 – Adding $4.5 + (-9) = -4.5$, not zero.
• C. 9.0 – Adding $4.5 + 9 = 13.5$, not zero.
• D. -4.5 – Adding $4.5 + (-4.5) = 0$, which is correct.

Thus, the correct answer is:

D. -4.5

Would you like further details on this solution, or do you have any questions?

Here are five related questions you might find helpful:

1. What is the concept of additive inverses, and why is it useful?
2. How can we visually confirm additive inverses on a number line?
3. How would the solution change if the number on the line was negative?
4. Why does subtracting a number result in moving left on the number line?
5. How can this concept be applied to solve real-life problems involving balances?

Tip: Remember, the additive inverse of a number is simply the opposite sign of the original number, and it always sums to zero with the original number.