Jyl Hewston, Robert Morse and Joe Mori, three performers who constitute the Plexus Mine Theatre, sat in the teachers' lounge at Woodlin Elementary School in Silver Spring, literally comparing notes.

They had just visited classrooms, met the teachers and students and had taken notes on class projects and problems. The notes would help them plan a program they were to present for the children five days later.

Plexus is one of dozens of groups chosen to perform in Montgomery County schools, after auditioning before a committee of PTA members, parents and Title One school staff members.Under provisions of the Elementary and Secondary Act of 1965, Title One schools are defined as those located in disadvantaged communities and are eligible for federal funds to be used for supplementary educational projects.

One of the aims of the program is to bring in diverse performing arts groups to help culturally and socially underprivileged children who are behind in reading and language arts. Results of standardized tests, given biannually, plus the number of poverty-level students and students in public housing determine a school's eligibility for funds. The money is matched by PTA's, at the rate of $2.50 per student, and sometimes is supplemented in Maryland by the state arts council.

The groups selected to perform in the 36 Montgomery schools designated for Title One-financed arts programs involve the children in their presentations, help motivate the students and help them develop a positive self-concept. This year's performers include an authentic, traditional American Indian in a program of folklore and culture, a magician, puppets and a group that introduces opera to children.

Toole Minton, Montgomery Title One program coordinator, could tell from the audition that Plexus would be a hit with children.

"They did marvelous, clear characterizations and showed good wit. Our committee acted out as though the children would, and the group had no trouble involving us on stage or controlling us."

Minton said Plexus has had experience in performing for children while touring Prince George's schools as part of a CETA-funded project.

Mime enjoys a widespread popularity because it demonstrates how ideas can be expressed without conversation and gives children and parents something to share at home.

Plexus members deal with the problem of how to bring children "back down after a performance" by teaching them mime technique, gestures and symbols, which comprise the art of imitation. Body awareness exercises, expression-making and mimicking daily activities "calm them down and make them personally committed to what is being taught," said one of the mimes.

Students become involved in the group's performance when a few are chosen to come on stage, wear masks or pretend to be anything from the wind to a big bed.

At Woodlin recently, parents and younger brothers and sisters sat absorbed in the Plexus show, listening to the multicultural students -- including Senegalese, Cambodian, Vietnamese, Hindi, Panamanian and Liberian -- call out the words on signs held up by the mimes: "only one chair," "roller coaster" and "grumps," to name some.

After the performance, students returned to their classrooms and parents asked questions of the actors.

"How young can children begin mime?" asked a parent.

"As soon as they can understand imitation," was the answer.

"If my son starts juggling around the house after seeing you today, how do I control him?"

"Start him out with bean bags -- they're soft. Establish where it's okay to juggle in your house," advised one mime.

Coordinator Minton was optimistic that parents would "realize the arts-in-the-school programs were supplementary to classroom work. It's not fluff or transitory entertainment."

Principal Donald Pfau said he considers the Title One program "a real godsend for Woodlin. Very talented people come into the school."