"What should be added to (8)/(14) to get (-2)/(7)?"

The question asks: "What should be added to $\frac{8}{14}$ to get $\frac{-2}{7}$?"
Let the number to be added be $x$.
So, we can write the equation:

$$\frac{8}{14} + x = \frac{-2}{7}$$

Both 8 and 14 are divisible by 2.

$$\frac{8}{14} = \frac{8 \div 2}{14 \div 2} = \frac{4}{7}$$

Now the equation becomes:

$$\frac{4}{7} + x = \frac{-2}{7}$$

Since the denominators are already the same, subtract the numerators.

$$x = \frac{-2 - 4}{7}$$ $$x = \frac{-6}{7}$$

The number that should be added is $\frac{-6}{7}$.