Room number in mailing address

[MikeNewYork]

What difference does it make if it is understandable?

 

[Tarheel]

Allow me to ask you again. If you write the name of the apartment building and the room number, would you write the number BEFORE or AFTER the building name? Which?

Also, is the sharp necessary before the room number?

Maybe they use a building name in Japan, but here we use a street address. Also, you can put "#" before the apartment number or use "apt" instead. (Use the abbreviation with or without the period.)