Let the unknown number be represented as \( x \). According to the problem, we can set up the following equation based on the information provided:
\[ 10 \times (x + (-1)) = -40 \]
This simplifies to:
\[ 10 \times (x - 1) = -40 \]
Next, divide both sides of the equation by 10:
\[ x - 1 = -4 \]
Now, to solve for \( x \), add 1 to both sides:
\[ x = -4 + 1 \] \[ x = -3 \]
Thus, the number is:
\[-3\]
The correct response is \(-3\) or negative 3.