ST. LOUIS - As they worked, they channeled their inner Hannah Montanas: "It's the beeest of both worlds," their little voices sang. Next door, in Sylvia Bronner's class, the group of only boys teetered on stools at their tables, if they sat at all.
They blurted possible answers in a raucous numbers guessing game. "A billion?" Bronner responded to one boy's guess. "It needs to be lower than a billion."
"One hundred sixty-two!" another boy blurted out.
An experiment in single-sex classrooms that started two years ago at Carman Trails school in the Parkway School District in the St. Louis area is winning over parents, students and teachers. And even though the school doesn't have test data to prove its success, the program is growing.
Last year, the school limited the same-sex classrooms to first grade. This year, it started them in second grade. And just last week, after meeting with enthusiastic parents, the teachers and principal Chris Raeker decided to offer the option in third grade.
Private schools in St. Louis have offered single-sex education for decades. But more public schools are giving it a try and liking the results. A charter school in St. Louis, the Imagine Academy of Academic Successes, and the high school and middle schools in East St. Louis are among the 500 or so public schools across the nation to try single-sex classrooms.
The U.S. Department of Education noted in 2005 that the jury was still out on the effectiveness of same-gender classrooms, due to "a dearth of quality studies" on the topic. But a lack of data hasn't slowed the popularity of the approach, which has been triggered by recent research that suggests the brains of boys and girls develop differently at young ages.
Raeker turned to single-sex classrooms while trying to figure out why younger boys were getting lower test scores and getting sent to the office more frequently. The boys were also going to the nurse's office more often, not coming to school as often and not participating in clubs as much as girls.
"There were so many different indicators that said we need to look at these guys and see what's going on," she said.
School leaders sought advice from Leonard Sax, founder of the National Association for Single Sex Public Education. When the group started in 2002, it counted 11 public schools that offered single-sex classes. Today, it counts at least 518.
Groups like the American Civil Liberties Union and the National Organization for Women have spoken out against separating boys and girls in schools, saying such classrooms are illegal and discriminatory. Others say the approach promotes gender stereotypes and fails to prepare students for a world where both sexes work together.
Raeker is familiar with those arguments. "We are absolutely committed to just the opposite, to letting girls know there's nothing they can't do," she said. She points out that parents get to choose whether to send their child to a mixed or single-gender classroom.
Sax said there are advantages to continuing to offer single-sex classes to students as they get older. As girls mature, he said, some show less interest in subjects like computer science, though fourth-grade girls actually outperform fourth-grade boys in math.
As boys get older, for some it becomes "cool" to not like school and to disrespect the teacher, Sax said. "It's great to start in the younger years, as Carman Trails has done, so you can create a different culture where boys think it's cool to be smart," he said.
But even in first and second grades, Sax said, the gender differences are apparent.
For boys this age, he said, it's not easy to sit down and be quiet like a typical teacher might ask of them. Which is why the boys move around from activity to activity, stand at their desks or teeter on stools, and love to compete and take on challenges.
"Now, I want to see if I can trick you," second-grade teacher Diandra Maguire recently told her class of boys during an activity on telling time.
Such tactics won't necessarily work for girls, the school's teachers say. Girls' second-grade teacher Cindy Rudman dares not tell her class she is going to "trick" them. "I know five that would be in tears," she said.
The teachers present the same information to the boys and girls, but present it differently. Advocates of single-gender instruction say boys seem to learn better if they are presented a concept first, then allowed to experience it before coming back as a group to discuss it. Girls, they say, learn better if they talk about the concept first and then attack an activity on their own.
Supporters of single-gender instruction also point to research suggesting that girls underestimate their own abilities, while boys have unrealistically high expectations of what they can accomplish.
"Boys think they have the answer right away, I say, prove it for me," said Maguire. "Now I think they're thinking about how they get the answers."
"I definitely see a self-confidence thing," said Alicia Wall, the first-grade teacher. "The girls are ready to learn and ready to work. In other classes, they're afraid to say something. They're afraid to be wrong."
While Carman Trails has no empirical data to show that single-gender classes are improving student performance, the school is confident it's on the right track.
School leaders say students in the same-sex classrooms are enthusiastic. The boys are becoming better writers, which is something boys that age aren't particularly strong at, says principal Raeker. Next year, they will tackle some research, have some standardized state test scores to look at in third grade and will hopefully see results, Raeker says.
For now, they bask in success stories of individuals like Lucas Reeder.
Lucas, 7, is in the all-boys first-grade class and was diagnosed with attention deficit disorder. His reading and writing have improved, and he loves being able to move around the classroom.
"We don't get calls saying 'he's been having problems concentrating' anymore," says his father, Michael Reeder. "I constantly get compliments from the people at school about what a sweet little boy he is. And it's nice to see that he's thriving in his environment."