Whether she's assigning a problem, or helping students work out the answer, professor Zvezdelina Stankova is passionate about one thing: math.
"For me, mathematics is very, very beautiful," says Stankova.
Stankova wants young girls to feel the same way.
She says "math circles" may be the key. They are weekly afterschool groups that make learning math fun. Complicated problems become intriguing games.
Stankova says a math circle was what inspired her as a young student in Bulgaria.
"That's where I saw problems that were so interesting and so engaging," Stankova said. "No one ever told me math was too hard for girls."
In 1987 she represented her country in the International Math Olympiads.
But statistics show American girls lose interest in math as they get older.
While 81 percent of elementary school girls report liking math, that number drops to 61 percent once they reach high school.
Stankova says her math circles are keeping girls interested, and her students agree.
"Math seems straightforward; but then there's also times when it's not, when it's super creative and you can make up problems," Francis Campbell, one of Stankova's students says.
University of Missouri researchers found a possible reason why boys pull ahead in math.
They followed 300 students from first to sixth grade and found boys called out more answers in class during the first two years but also had more wrong answers.
By sixth grade, the boys were still answering more problems than girls and were also getting more correct.
The researchers believe the boys' impulsive strategy of calling out the answers seems to benefit them in the long run.