>>No, the Washington is indeed a state. However, the District of Columbia is not a state. But I do not see how should we define it otherwise, so I would think you need to keep everything as you currently have.
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>So, in general, when we say 52 States for United States, it means those 52 are not all considered States. So, basically, out of 52, how many are States?

I always knew 50 states for US. However, I'm not an authority on the subject, so I would appreciate more the answers of natives.