Let's solve the expression step by step:

$- \left| (-1) + 3 \right|$

1. Start by simplifying inside the absolute value: $(-1) + 3 = 2$

2. Now, apply the absolute value: $|2| = 2$

3. Finally, apply the negative sign outside the absolute value: $-2$

So, the result of the expression $- \left| (-1) + 3 \right|$ is $-2$.

Would you like more details or have any questions?

Here are 5 related questions for practice:

1. What is the result of $- \left| (-4) + 6 \right|$?
2. Solve $\left| (-2) - 5 \right|$.
3. What is $\left| (-3) + (-7) \right|$?
4. Simplify $- \left| 3 - (-2) \right|$.
5. Calculate $- \left| (-5) + 8 \right|$.

Tip: Always simplify the expression inside the absolute value before applying the absolute value operation.