With a big yellow happy face pasted next to the perfect score he got on his math test, Juan Tejeda, 9, beamed with confidence.

"Now I know my 0 through 5s," he said, referring to the first set of multiplication tables he had just officially mastered.

His name would now appear on a list with those of other third-graders who had passed the test at Arroyo West School in Moorpark.

Since the school opened four years ago, the students in its nine third-grade classes have consistently ranked in the top 10% nationally on a standardized math test.

"I don't really know why," said Principal Juanita Suarez.

Teachers and school officials say they are doing a number of things right, but apart from the high scores, the math curriculum at Arroyo West is the same as it is at other schools in the district. In 1991-92 on the Comprehensive Test of Basic Skills, the students scored in the top 93rd percentile nationwide, in 1992-93 they scored in the top 94th percentile, and in 1993-94 they scored in the top 91st percentile.

"There are a number of factors, but I can't point to any single one," Suarez said.

Third-grade students throughout the Moorpark School District have received high scores on the standardized math test, but no other school has topped Arroyo West, which consistently scores 10 to 15 percentage points higher than the other schools. Teachers districtwide take math seminars throughout the year, said Suarez, and all the schools use the same math books and lessons.

More than 10 years ago, the district adopted the Bellwork math lessons, short five- and 10-minute exercises given at the beginning of the school day and after other breaks throughout the day. Previously, students would take several minutes to settle into their chairs at the beginning of a lesson. Now, they walk into a classroom and immediately tackle a problem written on the board at the front of the room.

"We fill up all the minutes in the day," Suarez said. "And the problems reinforce what they learn."

Another factor in Arroyo West's success at teaching math is parent participation.

"This is obviously out of our control, but perhaps the parents here have more of an opportunity to be involved with their children's school work," she said. "And perhaps the children have access to resources, like computers, that makes it easier to learn math."

Suarez finally points to the teachers at Arroyo West, who are constantly volunteering to take seminars to learn the latest teaching techniques.

Lisa Daniels teaches a pilot math class to Arroyo West third-graders. She said the teachers' enthusiasm for innovative lessons contributes to their success, and the students feed off this pride in the school.

With a crowd of students sitting in front of her on Friday, Daniels wrote a problem on the board: If you had four cars, three tricycles and seven unicycles, how many wheels would you have?

Emerald Briones, 8, carefully makes a mark on a piece of paper for each wheel, and then counts them out.

"Thirty-two," she says to herself, and then says, "I did it," while raising her hand.

The class quickly goes through problems and Daniels playfully asks students to explain how they got their answers.

"We want to emphasize problem solving," she said. "There are a lot of different ways to solve a problem."

Along with a foundation in problem solving, the students are placed in groups that fit their styles of learning, said teacher Linda Elmore.

"Some work independently, some need a little hand-holding and a little more calm," she said.

Whatever factors have come together to contribute to the students' success in math, the teachers are pleased with the results.

"We look at the trend, and we are consistently strong in math," Suarez said. "It's nice to know that we are doing good things here. It's nice to know that we are succeeding."