<prompt> Translate the following text to EnglishKwa mfano, punguzo laweza kutolewa kwa barua iliyopangwa mapema katika vifurushi, kila kifurushi kikiwa kwa eneo moja la nambari ya posta ya tarakimu tano.  <response>: For example, a discount could be given for mail presorted into packages, each package being for one 5-digit ZIP Code area. 