The price of postage for a letter always has been the best bargain in America. Millions of lovers have kept romance alive by letters. Families keep close ties through the mail. Even if postage goes up to 20 cents, it will be cheaper than a candy bar.

But a real problem will arise at Christmas time when people on fixed incomes try to send cards. It will be $1 to mail five cards, in addition to the cost of buying the cards.

Perhaps the Postal Service could have a reduced rate, say 10 cents, for Christmas cards mailed between Dec. 1 and Dec. 15. That would encourage many people to mail early.

These special greeting would not have to be treated with the urgency of first-class mail, but could be delivered at the convenience of the Post Office anytime before Christmas.

Such mail should carry a stamp with a special shape, such as a triangle (the shape of a Christmas tree) or a circle (the shape of a wreath) so that postal computers could pick them out. The stamps would bring in an extra big profit for the Postal Service in sales to collectors al over the world.

ROBERT A. BROTHERS,

Philadelphia

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One of the objections to the postmaster general's proposal for a nine-digit ZIP code is that people will not be able to remember it. Yet people remember their telephone number, which, with area code, has 10 digits. Most people, I believe, remember their Social Security number, which has nine digits.

With increased computerization, there may come a time when the human brain will be unable to handle all the numbers. But before that time comes, I believe that modern technology will have a solution. For example, we could use the same number for all purposes -- Social Security, telephone, care license, ZIP code, driver's license, etc.

I favor letting the postmaster general have his nine digits, if it will improve the mail service.

WILLIAM M. LEFFINGWELL

Washington