Regarding the article Frontline Literate Voice," Oct. 3: Producer David Fanning has a Sisyphean task if he is accurately quoted as "doing television for the highest common denominator." Schoolchildren learn to add fractions by writing them as equivalent fractions with the lowest common denominator. A highest common denominator can never be found, because doubling the one you have always gives you a larger one.Harold P. Boas, College Station, Texas Letters are welcome. Only a selection can be published, subject to condensation, and none acknowledged. Please address them to "Readers Write," One Norway St., Boston, MA 02115.