Following her lead

Betty Davis gave her Boston Latin School seniors a choice: Learn to ballroom dance for the senior prom or study calculus.

After a day of trigonometric equations, Anderson Boone threw down his pencil and decided to waltz. "It's better than math class," he said with a shrug. "I'll say that for it."

Davis said her free dance lessons are introducing the smooth discipline of waltz, rumba, and cha cha to a generation of students who "jump up and down" and call it dancing. For five years, she has been replacing math class with dance lessons after exams are finished and the school year is almost over.

The lessons will take new importance at the June 4 prom in the elegant Fairmont Copley Plaza. For the first time, Boston Latin will reserve 30 minutes of the 5 1/2 hours for ballroom dancing, or, as the students call it, Mrs. Davis's music.

Davis, a teacher for 34 years, the last 12 at Latin, embraced ballroom dancing five years ago for her daughter's wedding. Like her students, she had never danced ballroom style . At 5 feet 11, she had refused to wear high heels. She has made two exceptions: for President George W. Bush's visit to the school and for dancing, especially the waltz.

"It's just beautiful," she said dreamily. "It flows."

One day she mentioned her new passion to her students. To her surprise, students begged her to teach them.

They started with lessons for seniors in the final weeks of school. Last year, they launched a ballroom dancing club. This year, she and her dance instructor added two after-school sessions to meet the demand.

"I. Love. It," said Maya Stroshane, 17, breathing each word. "When I flail about, it's fun because of the freedom. When you're doing steps like this, it's to do something well."

Davis dubbed her class the "prom survival course" and decided to teach the basics: swing, waltz, rumba, cha cha, and salsa, with a dash of disco for fun. She shows them the box step, a basic turn, and side-by-side turns. At a school where girls outnumber boys, she teaches the girls to lead, so they can dance on their own.

At one class last week, two-dozen students lined up in a boxy lobby outside the gym. Davis slid an iPod into a speaker, and Norah Jones's "Come Away with Me" floated into the room. "Let's show them what we can do," she said.

Wearing flats, flip-flops, or sneakers, students flitted and flounced, twirled and tapped, slid and sashayed. They crashed into one another and apologized. Then a moody waltz bounced off the cinderblock walls. Backs straightened and eyes locked.

Suddenly, they were dancing.

"One, two, three," Davis called out, clapping with each beat. "Four, five, six."

Anderson, known as Andy, would rather have been reading science fiction, and he still refuses to go to the prom. But he patiently led the dances, the tallest in class at 6 feet 6. He tried not to step on Giselle Eng, his 5-foot-2 partner, with his size-16 sneakers.

"Come on Andy," Eng chided him when he faced the wrong way.

"You can always . . . lead," he told her. "I won't complain."

Maria Sacchetti can be reached at msacchetti@globe.com.