1. Take bus number 117 and get off at City Hall.

2. Take the number 117 bus and get off at the City Hall.
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Which one is correct? #1 or #2?
Do we have to put 'the' before 'City Hall"?
How do we read '117' here?

1. one seventeen
2. one hundred seventeen

Three questions:

We would say "the one-seventeen" or the "nineteen", etc.

Since most cities have only one City Hall, "the" is not necessary, but is quite proper.

Both 1 and 2 are correct. The number nineteen bus or the number one-seventeen bus. It is assumed you mean a bus, since taxicabs, etc., are nut numbered as buses are.