BLACKSBURG, Va. — There are no professors in Virginia Tech’s largest classroom, only a sea of computers and red plastic cups.

In the Math Emporium, the computer is king, and instructors are reduced to roving guides. Lessons are self-paced, and help is delivered “on demand” in a vast, windowless lab that is open 24 hours a day because computers never tire. A student in need of human aid plants a red cup atop a monitor.

The Emporium is the Wal-Mart of higher education, a triumph in economy of scale and a glimpse at a possible future of computer-led learning. Eight thousand students a year take introductory math in a space that once housed a discount department store. Four math instructors, none of them professors, lead seven courses with enrollments of 200 to 2,000. Students walk to class through a shopping mall, past a health club and a tanning salon, as ambient Muzak plays.

It sounds like the antithesis of the collegiate ideal — a journey of learning shared by students and faculty. Parents sometimes ask why their children are not getting more professorial face time in math when they are spending $17,365 (in-state) or $31,336 (out-of-state) in tuition, fees and living expenses to attend the prestigious public university.

But Virginia Tech students pass introductory math courses at a higher rate now than 15 years ago, when the Emporium was built. And research has found the teaching model trims per-student expense by more than one-third, vital savings for public institutions with dwindling state support.

“When I first came here, I was like, ‘This is the dumbest thing ever,’” said Mike Bilynsky, a freshman from Epping, N.H., who is taking calculus. “But it works.”

No academic initiative has delivered more handsomely on the oft-stated promise of efficiency via technology in higher education, said Carol Twigg, president of the National Center for Academic Transformation, a nonprofit that studies technological innovations to improve learning and reduce cost. She calls the Emporium “a solution to the math problem” in colleges.

It may be an idea whose time has come. Since its creation in 1997, the Emporium model has spread to the universities of Alabama and Idaho (in 2000) and to Louisiana State University (in 2004). Interest has swelled as of late; Twigg says the Emporium has been adopted by about 100 schools.

“How could computers not change mathematics?” said Peter Haskell, math department chairman at Virginia Tech. “How could they not change higher education? They’ve changed everything else.”

Emporium courses include pre-calculus, calculus, trigonometry and geometry, subjects taken mostly by freshmen to satisfy math requirements. The format seems to work best in subjects that stress skill development — such as solving problems over and over. Computer-led lessons show promise for remedial English instruction and perhaps foreign language, Twigg said. Machines will never replace humans in poetry seminars.

Computer-based problem sets and online lectures are now commonplace at Caltech, Georgia Tech, MIT and Purdue. Leaders in the math-science community applaud Virginia Tech for its innovation.

“I’m a strong believer in the experimentation that’s going on now,” said Jean-Lou Chameau, president of Caltech. “More and more of our professors, all of the materials they are going to provide in class are available online.”

But none of those top tech schools has yet embraced a fully “computer-mediated” math course.

“I don’t see it replacing the kind of high-level instruction that takes place here,” said Doug Ulmer, math chairman at Georgia Tech.

In the Emporium, the computer is teacher. Even after 15 years, that represents radical change.

University Mall in Blacksburg was a dying hulk when Virginia Tech swept in to renovate the old Roses department store, a $2 million transformation that yielded 60,000 square feet of teaching space and 537 computers arranged in six-person pods.

It was an experiment born of desperation. In the mid-1990s, Virginia Tech was growing and state subsidies were shrinking, forcing faculty cuts. Classes were being taught in a basketball arena, and labs were running past 11 p.m.

Emporium designers removed all the strictures of the conventional university class. Instead of attending three lectures a week, students could come to the lab when they pleased. Instead of 100 instructors leading hundreds of class sections, a rotating staff of about 12 would roam the lab, dispensing help as needed.

The lab now accommodates 5,000 students in fall and 3,000 in spring, freeing up dozens of Virginia Tech classrooms.

“You don’t have to have a big lab to do what we do,” said Terri Bourdon, the senior math instructor who runs the Emporium. “You don’t have to have the big staff that we have. You just have to have the philosophy that we have, which is that you learn math by doing math.”