More than three years after Montgomery County school officials started tangling with the sensitive issues of racial balance and school closing, the Board of Education found itself last night facing an angry crowd of nearly 1,000 Silver Spring parents and students ready to argue the same issues.

At the heart of the debate last night at the first of two public hearings on school facilities was the proposed closing of Northwood High School, the last of 28 schools originally set for closing in 1981.

Students and parents from Northwood, speaking for 1 1/2 hours and offering arguments that were often interrupted by cheers and applause from a near capacity crowd at Wheaton High School, were making a dramatic last stand in their battle to save a neighborhood school.

The board plans to vote Monday to determine the school's future. "The numbers are different, the facts are different in 1985," said Freddie Hodges, leader of Northwood Community Solidarity and the spokeswoman who has headed the drive to save the school. "We deserve the integrity associated with open-minded decision making."

School principal Bob Mullis said before the hearing that "the data and the original reasons for closing the school are completely different now. In 1981 the school planners said there would be 78,000 students in the district by 1990. This year they're projecting 103,000 students by that time."

Northwood High, a rambling structure off University Boulevard, was originally set to be closed in June 1984 as part of a cost-saving measure during a time of declining enrollments in the county. The closing was later delayed for a year and, this school year, the board was told by Superintendent Wilmer S. Cody that it might again have to reconsider the issue in the face of increasing enrollment -- the first such increase in 12 years.

Cody later recommended that the board stick with its original decision. To continue to use Northwood would take $9 million, he said, a cost that would be prohibitive as the system strives to build schools in upper Montgomery County. Supporters of Northwood questioned those figures last night and said the total was too high for what should be "modest improvements."

"The days of Lord and Taylor renovations are over," Hodges said. We must find alternative ways to modernize facilities.

According to Cody's recommendations the 900 students now attending Northwood would be split among Blair, Einstein and Kennedy high schools. Northwood parents pointed to Blair High School -- whose racial mix was at issue during school closure hearings three years ago -- and wondered aloud if their school was being closed in order to lower the percentage of minority students there.

"The easy solution is to close us," Hodges said. "The more difficult decision is to keep us open. To keep us open means you'll have to be more creative in your solution" to the problem of racial imbalance.

According to school board policy, when a school has a minority population 20 percentage points higher than the county average, the school board is to monitor the school. In September 1984, the countywide school average was 71.3 percent majority students and 28.7 percent minority. Blair High, a school that the board continually monitors for ethnic and racial balance, now has a 67.5 percent minority population.

Over the past few weeks, school board members have been reviewing data submitted by community leaders and the school system's planning department. Last night they responded to the Northwood argument by asking for comparison cost figures for renovations at Northwood. "I think it is important to canvass the issue as thoroughly as we can," board President Robert Shoenberg said.