<P> For Post Office Boxes , the general ( but not invariable ) rule is that each box has its own ZIP + 4 code . The add - on code is often one of the following : the last four digits of the box number ( e.g. PO Box 107050 , Albany , NY 12201 - 7050 ) , zero plus the last three digits of the box number ( e.g. , PO Box 17727 , Eagle River , AK 99577 - 0727 ) , or , if the box number consists of fewer than four digits , enough zeros are attached to the front of the box number to produce a four - digit number ( e.g. , PO Box 77 , Juneau , AK 99750 - 0077 ) . However , there is no uniform rule , so the ZIP + 4 Code must be looked up individually for each box . </P>
<P> For Post Office Boxes , the general ( but not invariable ) rule is that each box has its own ZIP + 4 code . The add - on code is often one of the following : the last four digits of the box number ( e.g. PO Box 107050 , Albany , NY 12201 - 7050 ) , zero plus the last three digits of the box number ( e.g. , PO Box 17727 , Eagle River , AK 99577 - 0727 ) , or , if the box number consists of fewer than four digits , enough zeros are attached to the front of the box number to produce a four - digit number ( e.g. , PO Box 77 , Juneau , AK 99750 - 0077 ) . However , there is no uniform rule , so the ZIP + 4 Code must be looked up individually for each box . </P>
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the box number
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