This Medicare publication explains the current year Part B premium. It also shows the current deductibles, co-pays, & coinsurance amounts for Parts A & B
This Medicare publication explains in detail the rules for coordinating Medicare with existing Union or Employer group health insurance. In some cases, the group insurance must be primary to Medicare, & in other cases not.
This Medicare publication will explain the current issue with hospital admission as an inpatient vs an "observational " stay. The difference being you will be disqualified for the follow up Skilled Nursing Benefit if your overnight stay is billed as "Observational" instead of as an inpatient.
This Medicare publication gives a list of all Preventive services covered by Medicare at 100%, & not subject to the Part B Deductible.