You can not take anything inside the test room when you go for the PMP Certification Exam. Before entering the room you have to handover all of your belongings at the Prometric desk counter. They will keep it inside a locker and you will be given the key. You can only keep this key and your ID inside the test room.
You may also have to show them your empty pockets, and you will be checked with a metal detector.
The Prometric center will provide you the scratch paper for rough work, pencil, and ear plugs. Moreover, if you request them to provide you a calculator, they will do it.