`(-9)+ . . . . . . . .=-1`

Answer

To solve the equation \((-9) + \ldots = -1\), we can follow these steps:

1. **Identify the unknown**: Let's denote the unknown value that we need to find as \(x\). So, we can rewrite the equation as:
\[ -9 + x = -1 \]

2. **Isolate \(x\)**: To find \(x\), we need to isolate it on one side of the equation. We can do this by adding \(9\) to both sides of the equation:
\[ -9 + x + 9 = -1 + 9 \]
This simplifies to:
\[ x = -1 + 9 \]

3. **Calculate the right side**: Now, we perform the addition on the right side:
\[ -1 + 9 = 8 \]
So, we find:
\[ x = 8 \]

4. **Conclusion**: Therefore, the value that fills the blank is \(8\). We can verify this by substituting back into the original equation:
\[ -9 + 8 = -1 \]
This confirms that our solution is correct.

**Final Answer**: \(8\)

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