Donald Mokrauer stayed home from work yesterday to care for his son, Jonathan. Eleanor Milutinovich took her son to work with her at the National Geographic on Tuesday, and so did her colleague Pat Holland.

At the Federal Energy-Administration the problem of employees' children who are unexpectedly out of school has led management officials to investigate the possibility of setting up an emergency day-care center. Meanwhile, the student union at George Mason University in Fairfax is dotted with children watching television or making pictures with crayons they have brought from home.

With some 70 area schools closed this week by natural gas shortages and cold, hundreds of working parents and their children have been faced with a problem that usually crops up only occasionally. When the schools close, where do the children go?

The problem has become serious as some schools announced plans to close for as long as a week, local child experts and working parents say. Many parents have taken annual leave to stay home and take care of their children, or have used sick leave, leaving offices understaffed. Others have lost pay and in at least two cases have lost jobs for taking time off, according to a Fairfax County child care official.

"With such short notice, what can you do?" said Pat Holland of National Geographic's World magazine, who brought her 10-year-old son Robbie on Tuesday. "I live in a neighborhood where a lot of parents work, so when something like this happens we're all rushing after the same baby-sitter."

Almost half of all the school-age children in the United States have mothers who work, according to Labor Department statistics. In numbers, this is 21.7 million children out of the 44.1 million American children between ages 6 through 17.

The number of children with working mothers has more than doubled in the last 25 years even while the birth rate has declined, according to statistics. But most of these mothers - and fathers as well - are still walking the makeshift tightrope between baby sitters, after-school programs, before school programs, and neighborhood trade-offs.

"Parents have so few choices," said Virginia Burke, coordinator of the National Institutes of Health's day-care program. "If the school and the daycare center close, where do you go? To the next-door neighbor, who for a bottle of wine will take care of your kid. Or you get fired, and then you can't get unemployment - the circle never ends."

Burke and other child-care advocates say the problem requires a national subsidized child-care program, which has been proposed and defeated in the past.

Arlington County is an example of an area that has started to deal with the problem. An "extended day care" program provides for about 990 children, or one-tenth of the elementary school population, according to a school system spokesman.

For people like Holland, Mokrauer and Mulutinovich, who can leave their children at school as early as 7:30 a.m., the program is ideal. But when the schools close, as Arlington's did this week, they are faced with the same problems as working parents everywhere.

"It's terrible when you hear on the radio at work that you child's school is closing early," said Laurie Saperstone, a child-care counselor for Arlington County and the mother of two sons, ages 9 and 11. "You end up calling neighbors. Often you can't leave your office because of the weather, and because of your obligation to your job."

Millie Grant of Fairfax County's child-care office said a 1974 survey showed that at least 30,000 children under age 9 in the country had parents who work all day. The county pays for an extended day-care program for only 423 children.

"This week we've been getting calls from parents who suddenly need day care," she said. "I don't think we've been terribly successful in helping them because we're just not organized to cope with a winter like his."

Grant said her office suggests that parents in day-care centers organize cooperative baby-sitting, or consider a list of 82 people that have been approved for taking care of groups of children in their homes.

Leon Shelnutt runs the Piedmont School in Arlington, a private school designed for children of working parents. The school is open 52 weeks a year. Shelnutt said that in response to calls for help he will organize an extra class for 20 children next week. The Arlington School Board is scheduled to decide at tonight's meeting whether to keep the schools closed another week.

"It may be a little like a one-room country school," Shelnutt said, "but we'll manage."

Taking children to work is considered by most parents a purely emergency choice. Milutinovich and Holland happen to work for a children's magazine, and they shared supervision of the children so that each could get work done.

"They (the boys) tested some of the craft ideas (from the magazine)," Holland said, "But things got a lot easier after the cartoons went on at 2 p.m."

Civil service policy is that individual supervisors may permit their employees to bring children to work - or may chose to discourage the practice. Richard Bavier, a program analyst at the Social Security Administration, was able to bring his 8-year-old son to work one day "because my boss is good about it". The boy sometimes just stays in the public library near Bavier's Arlington office, he said.

The problem stems from the fact that in our society we do not see our children as our responsibility," Burke said. "People are going to have to realize that child care is not just for the poor, child care is for children."