Question

What does f 3.5 6.3 mean?

Answer 1

For example: if you look at the Olympus M. Zuiko Digital ED 12-200mm f/3.5-6.3, that means it's widest aperture at 12mm is f/3.5 and it's widest at 200mm is f/6.3. It does not mean that the smallest aperture available on the lens is f/6.3.