HUNTINGTON STATION, L.I.— Barbara Reiser felt pleased with her son Brian's new school after a teacher called last month with the results of the boy's first math test.
He had failed.
"Brian had never really been challenged in school before," Mrs. Reiser said. "But now he can't coast. It's a great learning experience for Brian. I expected him to be beside himself. But he handled it really well."
Brian is a 12-year-old who had become so bored at the public school he once attended that he would laugh at the textbooks. "Look, Mom," he would sometimes say at the start of a school year, "it's the same book I had last year only with a different cover."
But before Brian got lost in academic limbo, his parents enrolled him in the Long Island School for the Gifted, one of a few private schools in the nation whose classes are tailored to address the needs of bright children whose needs are not being met by the public schools.
The school, which requires I.Q.'s of at least 130, was founded in 1980 by Carol Yilmaz and a group of parents like her whose children found school boring and unchallenging. Mrs. Yilmaz's daughter Robyn, for example, had begun to sour on school by first grade because she was so far ahead of her peers.
Today, Robyn is a Harvard graduate, and the school her mother founded is flourishing, with 225 students. Last month, the school earned a rare distinction when two of its graduates were named the only New York State Advanced Placement Scholars for 1994. To be considered, a student must complete at least three college-level courses in high school. The two graduates of the school completed more than 10 such courses.
Mrs. Yilmaz sees the awards as confirmation of the critical role the school has played in cultivating the potential of the so-called gifted child.
"Every child deserves a good education," said Mrs. Yilmaz, who is now the school's director. "And gifted children need educations that challenge their unique abilities."
At a time when an increasing number of revenue-strapped school districts across New York State are eliminating programs for the gifted, schools like the one run by Mrs. Yilmaz are becoming alternatives of last resort for many children and their parents.
"The fact that districts are reducing programs for the gifted indicates that they don't see them as necessary as other programs," said Dr. David J. Irvine, who coordinates such programs for the State Department of Education. "That's why they are more vulnerable to changes in the economy."
Some parents and educators have long argued that classes for intellectually talented children are unnecessary, promote elitism and deprive other classes of brighter students.
In addition, critics say the special classes are merely a way to keep middle-class children in the public schools in places where students from poorer families, often black and Hispanic, predominate.
But advocates of such programs contend that intellectually talented children often become bored in mainstream classrooms and never develop the kind of good work habits that would help them get ahead.
Of the 40 million students in kindergarten through 12th grade nationwide, about two million can be classified as gifted, according to estimates by the Federal Department of Education. People who are considered gifted possess a wide range of talents, including I.Q.'s that are approximately 30 points above the average of 100.
"Many of these kids really need to be challenged in a special way in order for them to grow," said Roberta Tropper, the principal of the School for the Gifted. "But many people have this perception that gifted children don't need any special help because they already have an advantage. And that's just wrong."
Mrs. Yilmaz said that early on, Robyn felt frustrated with her schooling.
In nursery school, she was asked to color in letters with crayons even though she could already read. And by the first grade, Robyn knew how to multiply and divide while the rest of her class was learning to add and subtract.
"The school is really the product of a lot of frustration," Mrs. Yilmaz said. "That's why I can understand the anguish that so many parents feel in seeing their children not being challenged and becoming underachievers."
The school opened modestly, with 14 students inside the classroom of a synagogue in Freeport. Today, it shares a building with a branch of Adelphi University and has kindergarten through ninth-grade classes. Yearly tuition is $5,600 to $6,700, compared with the average annual per-pupil spending of $10,941 in public schools on Long Island and $8,556 statewide. The school has managed to keep tuition low by holding fund-raising drives and paying its teachers far less than the median for Long Island teachers of $62,898 a year.
Students are assigned to classes on the basis of their understanding of a subject rather than their age. So a child might be in a fourth-grade class for one subject and a fifth grade for another.
There are between 4 and 15 students in each class. They study advanced topics at a younger age than at other schools. In kindergarten, for instance, children are taught Spanish and science.
School officials take great pains to dispel the stereotype of these talented children as bookish and insulated. But the students display a decidedly academic flair, from humming along with the classical music that echoes through the hallways to discussing articles from newspapers that are handed out each day in homeroom.
A class of fourth graders seemed perfectly at ease probing the concept of positive and negative space during a recent lesson in contour drawing.
"I get it," Henry Mathies said, interrupting his teacher as she tried to explain the concept. "Can we start drawing now?"
Many parents say that their children would simply flounder without such a thought-provoking environment.
Consider the case of Carol Eisner of Lloyd Neck, L.I., who enrolled her 12-year-old son, Gregory, in the school five years ago. He had shown remarkable ability from early on, a boy who by age 3 could recite the lines in about a dozen storybooks.
"He would just say the words and turn the pages like he was reading," his mother said. "But he really wasn't reading. He had just memorized the stories from all the times we read to him."
He also developed a knack for math between the ages of 3 and 4. In a favorite drill, he would have his parents quiz him with math problems as they traveled in the family car. "Give me numbers," he would shout to them from the back seat.
But his intelligence seemed to become stifled when he began first grade at a public school.
One telling episode involved his refusal to complete several problems on the first page of his math book as his teacher had instructed him. Instead, Gregory did the harder problems on the last page.
Rather than encourage him, the teacher reprimanded Gregory.
"I just thank God we found the right school for him," Mrs. Eisner said. "Otherwise, he would have been lost."
Similarly, Brian Reiser, the boy who came to the School for the Gifted this year, had been complaining about school since fourth grade. To him, the subject matter had become painfully repetitious.
"The third grade was probably the last year I learned a decent amount of stuff," he said. "In the fourth grade, we basically reviewed what we learned in the third grade. And in the fifth grade, we reviewed what we learned in the fourth grade. There were some new things, but not enough."
His mother didn't know what to do. "I was at wits' end," she said, recalling Brian's occasional but emphatic collect phone calls from school. "He kept nagging and nagging."
But now he finds school stimulating and enjoyable. He has turned his math scores around by doing something that wasn't as necessary before: studying. "I've never really liked school," Brian said. "But this place is great -- for a school."
Photo: Kate Berson and Matthew Eisner, both 8, in a second-grade science class at the School for the Gifted. The students must have I.Q.'s of at least 130. (Vic DeLucia/The New York Times)