Step 1 :Calculate the number of choices for blue and green hats: \(2 \text{ sizes} \times 2 \text{ types} = 4 \text{ choices}\)
Step 2 :Calculate the number of choices for black hats: \(1 \text{ size} \times 1 \text{ type} = 1 \text{ choice}\)
Step 3 :Add the choices for each color: \(4 \text{ blue/green choices} + 1 \text{ black choice} = \boxed{9} \text{ total choices}\)