HARTFORD, Conn. — Elementary school students attended school in Sandy Hook on Monday for the first time since a shooting rampage there killed 20 first-graders and six educators.

Joseph Erardi, Newtown’s School Superintendent, said it was a great and uneventful day for the just under 400 students at the new 86,000-square-foot Sandy Hook Elementary School, which was built to replace the one torn down after the December 2012 shooting.

“I spent all day there and it felt the way that it should feel,” he said. “Students were excited to be there.”

The $50 million replacement was built on the same property as the former school, but not in the old footprint. All that remains are two large concrete slabs containing dinosaur footprints that also sat outside the old building.

About 70 current students attended the Sandy Hook Elementary School when the shooting occurred. School officials say about 35 of them were in the building at the time, but none witnessed the shootings. Those students, who were all in kindergarten at the time, are now fourth graders.

Erardi said he visited all of their classrooms and there were no issues.

Because of retirements and transfers, about 60 percent of the staff members from the original Sandy Hook are still with the school. Others left through retirement or job changes, and a handful chose to transfer as part of their recovery process, Erardi said

He credited parents for creating a smooth first day back for students, noting the vast majority of families took the time to tour the new school in advance of opening day to prepare the children.

“It was a back to business first day,” he said. “There was nothing extraordinary that took place with announcements with any type of ceremonies. Just off the bus and let’s go to work.”

After the shooting, Sandy Hook students attended a school in neighboring Monroe, which renovated a previously closed elementary school to serve as a temporary home for them.