Charles County school officials have come up with their own version of a scatter plan: Next fall, at least 25 of the county's 976 teachers will involuntarily leave their old classrooms for assignments at new schools as the county struggles to save teachers' jobs in the face of budget cuts.

But even as the opening of school approaches, officials are not sure where all of the teachers will be assigned. In some cases, says school superintendent John H. Bloom, there still is some mystery about which subjects they will teach.

"We're trying desperately not to lose teachers who want jobs," Bloom said. "The issue now is not whether they will have jobs. The only question is, where?"

The uncertainty resulting from shuffling teachers is a symptom of the county's efforts to offset dwindling federal and state support for education. School officials already have tried other methods to bolster the budget, including increasing student-teacher ratios and redirecting students to other schools.

The $41 million fiscal 1984 budget approved for the schools was $2.3 million less than school officials had hoped for. As a result, the school board eliminated plans for some new and existing programs and renegotiated its contract with the teachers in June. The revised contract lowered an existing 4 percent cost-of-living increase to 3 percent for all 1,716 employes in the school system. The teachers' union, the Education Association of Charles County, also agreed to rebid its health-care contract.

Because of the budget crunch, the get-aquainted, "computer literacy" program that officials had planned to institute in 26 elementary, middle and high schools is gone. With it went sessions for elementary school students in the county's planetarium, said C. Ashley Smith, administrative assistant to the superintendant. And driver education courses will be taught after school, with a $25 tuition fee.

But the money-stretching actions bear directly on the teachers, too. Most dramatic is the change in classroom sizes, with an average increase to 27 1/2 students in elementary classes and 25 1/2 in secondary schools.

"Regardless of how it is resolved, it is going to be disastrous as far as class size goes," said Cheryl Drinkard, former president of the teachers' union. "When you go it alone with 180 students per day , that gets unwieldy. In reality, the people may have jobs, but it's going to be the quality of teaching that will suffer."

School system officials said that most of the teachers who will be transferred are from secondary schools.

Some English and social studies teachers will be required to teach different courses. Secondary schools have experienced the brunt of the county's decline in enrollments, which dropped from 17,700 students system-wide in recent years to 16,600.

Smith said that transferring teachers will enable administators to avoid layoffs by placing teachers with low seniority in 25 to 30 positions that will become vacant this fall because of resignations and retirement. In better economic times, those positions would have been filled by new hires.

"It's too bad, but if you don't have the student load to support the job, we've got to move them," Smith said.

Drinkard said that the transfers will "definitely have a ripple effect all over the county. There won't be a school that isn't effected."

Smith said that one category of federal support for the school system has dropped from $1 million before President Reagan took office to $600,000 after his first year in office.

"Next year, we're anticipating nothing--zero--absolutely nothing from the federal government," Smith said. "But we're hoping Congress will change that."

Any new federal funds would be used to restore the computer-literacy program, and to increase employe health-care benefits, he said.