"Seven and one?" sings Robert Patton. "Eight," replies Susan Wright, exultation ringing in her exquisite soprano tone. It is a secondary climax (the big one comes when he stabs her to death a few minutes later) in a weird but charming one-act opera, "The Lesson," which had its world premiere during the four-day "'Operathon" just completed at Prince George's Publick Playhouse.

"The Lesson," composed by Thomas Cain to a libretto based on a play by Ionesco, is a short, zany-macabre surrealist comedy about murder and obsession -- certainly not everyone's cup of tea and unlikely to run at the Met in the near future. But it is skillfully crafted and holds the attention intensely during the 40-odd minutes it runs.

It shared honors at the Operation with another world premiere, "The Tell-Tale Heart," composed by Thomas Czenry-Hydzik and based on the story (also about murder and madness) by Edgar Allen Poe -- a tour de force for a solo soprano, who shares the stage for half an hour only with a dance and pictures projected on a large screen.

"The Tell-Tale Heart" was tailored specifically for Marilyn Cotlow, who retired to Maryland to raise a family after singing leading roles for several seasons at the Met (notably the world premiere of Menotti's "The Telephone"), and whose singing was undoubtedly the highlight of the Operathon's four days.

Many people go to the opera, one suspects, because of its air of decadent luxury -- expensive singers with foreign names, surrounded by lavish productions and making their pretty noises in an exotic language. This audience did not get to the Publick Playhouse, and it is just as well. World premiere or not, they would have been disappointed.

The Prince George's Civic Opera runs on a shoestring budget, and this was clear in the sparse staging of both operas and the chamber-music proportions of the orchestra. Lack of the kind of rehearsal time a world premiere requires was evident. The performances were like workshops or advanced rehearsals, with the singers reading from scores on stage and most of the scenery left to the imagination.

But the voices were all good. Besides Patton, Wright and Cotlow, they included Cynthia Beitman, who sang in "The Lesson."' She also sang the role of Hansel in two of the four matinee performances of "Hansel and Gretel" which ran concurrently with the evening's experimental operas.

Cain and Czerny-Hydzik are both young composers, just beginning to venture into opera, and both showed a high level of technical skill. They compose in the style of our times (which is more accessible than the style of a few years ago, but still "modern," and resolutely refuse to throw in anything like "La donn'e mobile" for the groundlings. But each showed a clear vision of how words and music interact dramatically, and they produced works one hopes to hear again.