The expression shown in the image is:

$-18 + 5 - 8$

Let's simplify this step-by-step:

1. First, add $-18$ and $5$: $-18 + 5 = -13$

2. Then subtract $8$ from $-13$: $-13 - 8 = -21$

So, the simplified result is:

$-21$

Would you like further clarification or more details on this?

Here are five related questions:

1. What is the general rule for adding and subtracting negative numbers?
2. How would you handle the expression if multiplication or division were involved?
3. Can this type of expression be represented on a number line?
4. How do negative numbers behave when squared?
5. What happens if we add or subtract fractions with negative numbers?

Tip: When adding or subtracting negative numbers, always think of the number line. Moving left represents subtraction, while moving right represents addition.