MOORESVILLE, N.C. — Sixty educators from across the nation roamed the halls and ringed the rooms of East Mooresville Intermediate School, searching for the secret formula. They found it in Erin Holsinger’s fifth-grade math class.

There, a boy peering into his school-issued MacBook blitzed through fractions by himself, determined to reach sixth-grade work by winter. Three desks away, a girl was struggling with basic multiplication — only 29 percent right, her screen said — and Ms. Holsinger knelt beside her to assist. Curiosity was fed and embarrassment avoided, as teacher connected with student through emotion far more than Wi-Fi.

“This is not about the technology,” Mark Edwards, superintendent of Mooresville Graded School District, would tell the visitors later over lunch. “It’s not about the box. It’s about changing the culture of instruction — preparing students for their future, not our past.”

As debate continues over whether schools invest wisely in technology — and whether it measurably improves student achievement — Mooresville, a modest community about 20 miles north of Charlotte best known as home to several Nascar teams and drivers, has quietly emerged as the de facto national model of the digital school.