Before 1995, all area codes had the form of NYZ, where the N was any digit from 2 to 9, Y was 0 or 1, and Z was 1-9. These restrictions on N saved 0 for call operater, and one for long distance calls. In addition, codes such as 800 and 911 were and still are used for special purposes. The restriction thay Y=0 or 1 was removed in 1995 because all possible area codes had been assigned. Today N is 2-9, Y is 0-8 and Z is 0-9; the exception to these rulesare codes of the form 37Z and 96Z, which are being reserved for future use. Area codes where Y=Z are called easily recognizable and are often assigned to special services.
1. How many area codes where possible before 1995?

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