Shau-uen solved the equation 18.5 w + 6.5 w minus 2.8 w = 149.1. Her work is shown below.

Step 1 18.5 w + 6.5 w minus 2.8 w = 149.10
Step 2 25 w minus 2.8 w = 149.1
Step 3 Negative 2.8 w = 5.964
Step 4 w = negative 2.13

In which step did Shau-uen make her first error?
Step 1
Step 2
Step 3
Step 4