The families of four children who were found guilty of setting a fire that caused $125,000 in damage at a Prince George's County elementary school in December were ordered yesterday to pay a total of $12,000 by a Juvenile Court Judge.

Judge Robert H. Mason, following the recommendations of attorneys on both sides, ordered the parents of the four boys to pay $3,000 each in restitution for the fire set Dec. 3 at Matthew Henson Elementary School, 8210 Scott Rd., Landover.

The total figure, $12,000, is believed to be the largest ever ordered by a judge in a juvenile case in Maryland. The maximum a single family can be ordered to pay under state law is $5,000.

Mason said last night the figures were worked out before the case came into court. "It wasn't much of a hearing," he said. "They were in and out. All they really needed was court sanction for what they had worked out."

Mason added that the attorneys on both sides had a agreed not to discuss the settlement or how it was reached. The names of the four boys, all from Palmer Park, were withheld because they are juveniles. The hearing was closed for the same reason. Two of the boys are 12 and two are 13.

Fire officials said that two separate fires were set in the building on Dec. 3, both in classrooms. Two firefighters were injured while fighting the two-alarm blaze.

Matthew Henson is an experimental "open school," in which the class-rooms are three or four times the size of a normal classroom.

All four boys had been charged with arson by fire officials.