To simplify the expression $-5 + 18$, you simply add the numbers:

$-5 + 18 = 13$

So, the result is $13$.

Would you like to go over any details or have further questions?

Relative Questions:

1. How would you handle the expression $-5 - 18$?
2. What is the result of $18 - 5$?
3. How can you visually represent $-5 + 18$ on a number line?
4. What happens if you add a negative number instead of a positive one to $-5$?
5. Can you think of a real-life situation where you might use the calculation $-5 + 18$?

Tip: When adding a negative number and a positive number, the result is the difference between their absolute values, taking the sign of the number with the larger absolute value.