Next weekend marks the beginning of National Metric Week, which was created to promote greater awareness and understanding of the metric system in the United States.

During this week, children will be bringing home math problems that feature metric measures, conversion tables showing English and metric units and stern admonitions about our country's reluctance to follow the rest of the world in adopting this most sensible of all systems of measurement.Well, like most of you, I remember very clearly the chidings from educators and legislators back in the 1970s about how we must "metrify" within the decade or else America would lose its pre-eminence in world trade.

But now it is clear that whatever decline America has suffered over the years has not been due to our children's inability to calculate measurements in the metric system, but rather to their inability to calculate measurements in ANY system.

The U.S. has not made an all-out effort of purge itself of its "outdated and illogical" system of measurement for a variety of reasons, most of which have nothing to do with measurements at all.

The English system is, after all, part of our culture, as are the phrases and images that it has spawned over the centuries, and culture just does not yield to easy conversion. (It would be strange, would it not, to hear that "28 grams of prevention is worth 453 grams of cure" or to picture a Texan in a "38-liter hat.")

Then, too, the "official" thrust to change has been blunted by the fact that change is taking place on its own. Americans are becoming familiar with buying soft drinks in 2-liter bottles, motorcycles and automobiles with engines measured in cubic centimeters, electricity in kilowatt hours, vitamins in milligrams, and on and on.

So, what attitude should a parent adopt upon hearing these renewed calls for "metrification" and in helping children with their metric homework problems this week?

First, I think, parents must convey the idea that all educated people in the world - including those in the U.S. - have at least some understanding of the metric system. It is important to know, for example, the meanings of the prefixes (such as milli-, centi-, and kilo-) because they provide clues to the meanings of so many English words and words in other languages as well.

Second, parents should stress the idea that it is much more important to be able to move about freely WITHIN either system than it is to move BETWEEN the systems. There is very little practical importance in deriving the precise Celsius temperature from a Fahrenheit thermometer. But children should be able to add and subtract metric measures, as well as English measures, accurately and then quickly.

Third, parents should encourage their children to develop a "feel" for metric amounts by focusing upon a few reference points that can allow children to make a thoughtful estimate of how amounts in one system compare with amounts in the other.

For example, a nickel weighs about 5 grams; the wire in a paper clip is about 1 millimeter wide; a cubic centimeter is about the size of a sugar cube; a thimble holds about 3 milliliters (1 tsp.

5 ml); normal body temperature (98.6 degrees F) is exactly 37 degrees Celsius.

You can help your children develop their own reference points by measuring and weighing common objects, and then having them estimate how other objects would compare, first in one system and then in the other.