5+8-9

The calculation of \( 5 + 8 - 9 \) can be simplified as follows:

1. First, add \( 5 + 8 = 13 \).
2. Then, subtract \( 9 \) from \( 13 \): \( 13 - 9 = 4 \).

So, \( 5 + 8 - 9 = 4 \).