Simplify the following text for a Grade 14 native English-speaking person.
Original: There are a total of 326 districts made up of 36 metropolitan boroughs , 32 London boroughs , 201 non-metropolitan districts , 55 unitary authorities , as well as the City of London and the Isles of Scilly which are also districts , but do not correspond to any of these categories .
Simplified: There are 36 metropolitan districts , 32 London boroughs , 238 non-metropolitan districts , 46 unitary authorities , the Isles of Scilly , and the City of London , making a total of 354 district-level authorities .