HOLLIS – When she talks about teaching mathematics, Stacey Plummer’s face lights up.

“If you spoke to one of my students, I hope that they would say that it’s obvious to them how much I love doing what I do, that my passion for both teaching and mathematics is evident,” said Plummer, a Hollis/Brookline High School mathematics teacher.

Plummer, who has been teaching mathematics for 16 years, has no need to worry. Few students and colleagues haven’t noticed the energy, thought and passion she puts into her job.

“Simply put, Stacey is one of the finest math teachers I have met in my 35 years of teaching,” wrote Dorothy Ball, chairwoman of the mathematics department at the high school, in supporting Plummer’s application for a national teaching award.

“The key word to describe Stacey’s approach to teaching, to mathematics and to life is passion.”

Last week, Plummer learned that a panel of judges from the National Science Foundation had selected her to receive a Presidential Award for Excellence in Mathematics and Science Teaching for 2009.

She was one of up to two mathematics and science teachers in each state and four U.S. territories named winners at the secondary school level.

The awards rotate: one year, they go to outstanding elementary school teachers, the next year, to secondary school teachers.

For Plummer, who has been coaching math teams for 15 years, the recognition validates the path she chose as a seventh-grader in Medway, Mass.

“Math challenged me. Even though I was a natural, it was the challenge that I appreciated,” she said.

“The interest was there from the beginning of school.”

Plummer graduated from high school in 1990, earned an undergraduate degree in mathematics at the University of Rochester, known for its engineering program, and taught at Merrimack High School for five years before joining the faculty at Hollis/Brookline High School 11 years ago.

She recently completed a graduate program for teachers at the University of New Hampshire.

“My goal is to make mathematics accessible to all of my students. I want all of them to be successful,” she said.

Plummer also wants her students, whether they are studying calculus, geometry or consumer mathematics, to understand that mathematics is a process that involves trial and error.

“I liked that it didn’t come easily. It was something to sink my teeth into and try,” she said. “A lot of times, the first, second try didn’t work. … What frustrates a lot of kids is if it doesn’t work the first time, they think, ‘I can’t do it.’”

Plummer said that early on, she had envisioned a career in mathematics that involved supporting scientists and engineers. She changed her mind before graduating from college.

“The more I thought about it, pictured myself sitting at a desk or in a cubicle, the more I had the feeling I wanted to do something to be giving back to society,” she said.

She also remembered that high school friends and teachers had told her more than once: “You need to teach.”

“I had a gift for breaking math down and explaining it. I helped friends,” Plummer said.

That ability made an impression on colleague Mark Illingwood, a past winner of the Presidential Award.

“Stacey Plummer is not one of the best math teachers I have encountered in teaching for 26 years in New Hampshire schools: she is the best,” Illingwood wrote in a recommendation to the National Science Foundation.

“I have been trying to convince her for several years to apply for the Presidential Award for Excellence in Science and Math Teaching. The problem has been that she is always too busy developing programs for her students or giving them extra time during her breaks and after school. She is also an incredibly modest person who works her magic for only her students and not for any accolades this may bring to herself.”

The first time Illingwood encouraged Plummer to apply for the award was seven years ago.

“I didn’t see myself as deserving,” Plummer said.

Also, the time wasn’t right the next time he encouraged her.

“I didn’t feel, with the ages of my children, I could take on the application,” she said, describing a detailed and lengthy application process that involved making a DVD of herself teaching.

Last year, the time was right.

“My department head really encouraged me. I’d just finished my master’s program and I had the time,” she said.

The award comes with a $10,000 prize and an all-expense-paid trip for two to Washington, D.C., including celebratory receptions, banquets, and professional development programs.

Plummer’s guest will be her husband, Craig, an educational consultant.

In past years, she said, the prize money has been earmarked for the school where the winner teaches.

But this year, the award goes to the teacher.

“I’d been thinking about how it could be used for the school, and I found out the award goes to me,” she said. “I’m still in shock.”

Hattie Bernstein can be reached at 673-3100 Ext. 24 or hbernstein@cabinet.com.