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. This academic year, Emporium-style math arrived at Montgomery College in Maryland and Northern Virginia Community College.

“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, nor has any other large public university around Washington.

“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.”

Students click their way through courses that unfold in a series of modules. Each lesson typically starts with an online lecture or reading passage, then leads to a series of problems. Students receive instant feedback; hints are dispensed and wrong answers explained. The module ends in a quiz. Faculty design every course and have added modest improvements over the years, such as interactive animation and embedded links that hark back to previous lessons.

Students are free to do course work online from dorm rooms but must come to the lab, which is a 15-minute walk or short drive from campus, for quizzes and tests. These are entirely multiple-choice, to eliminate hand-grading, and tightly monitored: Backpacks go in lockers, iPhones are turned off.

The teaching method pioneered at the Emporium solves two problems that have long vexed general math instruction. One is that lecture classes give students little chance to do math. The other is that students in basic math classes often span a wide range of ability and experience. Some have forgotten the material, while others never knew it. The lock-step pace left some students behind and held others back.

One recent afternoon, nearly every Emporium seat is filled, every mall parking space taken. Students file into the Emporium past a red, orange and white statue of the Virginia Tech Hokie — a large, imposing turkey rendered in Legos — past potted plants and a fountain and a sign that forbids cups without lids.

The lab is painted a calm, robin-egg blue. It is filled with late-model Macs; 200 new machines sit in a storage room, awaiting deployment.

Nicholas Gratto, a freshman from Manorville, N.Y., plants a red cup atop his monitor. He is stuck on a problem in Math 1526, a calculus course for prospective business majors. A teaching assistant appears.

“Okay,” she says. “We know that revenue equals price times quantity.” She recites a formula. “That’s going to be our price times our quality. Are you with me so far?”

TAs are trained to guide students toward answers rather provide the answers. Interventions are supposed to take no more than a few minutes.

The TA writes some more formulas, then tells Gratto, “I’m going to let you go from here.”

Faculty remain neutral or vaguely displeased with the Emporium, Haskell said, partly because they were not allowed much say in its creation.

Students seem to appreciate and resent the freedom the Emporium affords.

“I don’t have to go to class, which is nice,” said Lauren Goff, a freshman from Faber, Va. “But I kind of wish for this subject we did have a class. I’m one of those people who can’t learn just by looking at a computer. I have to be shown something.”

Parents have their own questions. One section of the Emporium Web site speaks to parental concerns, such as: The Math Emporium seems so large and impersonal. Why would my daughter want to be there?

Some resent the financial motives behind the Emporium. The format offers an extreme example of the savings universities attain by holding 400-student lecture courses, in order to steer funding toward more costly academic offerings.

“It’s not the money to me so much as it is the teaching aspect. In a way, it shortchanges the students,” said Larry Goff, Lauren’s father. “Lord knows I had a hard time in math, and I had teachers.”