Removed "RANDOM" from public enum Operation.
It was not needed.
Added "throws UnsupportedOperationException" to the Method construction.
Added "throws UnsupportedOperationException" to the implemented Methods.
Added "throws UnsupportedOperationException" to the implemented Methods.
Completed these tasks within the GUI:
1: Layout of the GUI
2: Wiring up the fields to the logic
3: Error Handling
4: User input validation
5: User feedback