Finding the Missing Number in (+15) + (-4) + □ to Make a Negative Sum

To solve this problem, follow these steps:

• Step 1: Calculate the sum of the two provided numbers.
• Step 2: Determine the number that will keep the entire sum negative.
• Step 3: Compare with the given choices and select the correct one.

Now, let’s calculate step-by-step:

Step 1: Calculate $+15 + (-4)$.
This results in $15 - 4 = 11$.

Step 2: We need to find a number $x$ such that:

$11 + x < 0$.

Solving for $x$:

$x < 0 - 11$

$x < -11$

Step 3: From the choices provided, only $-12$ satisfies this inequality. Thus, the number that can be inserted to make the sum negative is:

$-12$