A teacher stands before a green chalkboard at the KIPP Academy and asks if anyone’s ever seen a building being built. Almost an entire classroom-worth of hands shoots up.

“What’s wrong with starting on the 12th floor?” the teacher, David Nieder, asks the room of new fifth-graders.

“It has nothing to hold it up,” one girl answers.

“Who can repeat what she just said?” Mr. Nieder asks.

“There’s no base on it,” a boy says.

Mr. Nieder then launches into a theatrical, half-hour multiplication lesson that has a classroom of 10-yearolds clamoring to recite the nine times table.

While the vast majority of New York City schoolchildren spent yesterday watching television or hanging out with friends, 96% of KIPP Academy Charter School students reported to class for Day 1 of summer school.

At KIPP – where about 80% of eighth-graders meet or exceed standards on statewide reading and math exams, compared to a citywide public school passing rate of about 35% – summer school is for everyone, not just struggling students.

Instead of being an addendum to the normal school year to help failing students learn what they missed between September and June, KIPP’s summer school is considered the start of the new year.

That means the pupils who were seventh-graders on June 24 officially became KIPP’s eighth-graders, and a new crop of the school’s youngest children, fifth-graders, started learning KIPP’s distinctive vocabulary and rules.

“I think it’s another instrumental part of what we do,” said the school’s principal, Quinton Vance, who greeted the children when they arrived to school, orchestrated their high-five filled entry into the building, and lingered outside after class started, offering his cell-phone number to parents with questions.

“Our goal is to get our children ready to succeed in high school and in college,” he said. “We want to get our kids ready so when they walk in the door in September they’re ready to go.”

David Levin, the founder of the Knowledge Is Power Program, which runs 31 KIPP schools nationally, said the first day of summer school is his “favorite day, just to see everyone here and excited and learning.”

After a lesson on “Romeo and Juliet,” KIPP English teacher Mayme Hostetter said children learn a “great deal” coming to school from 8 a.m. until 2 p.m. Monday through Friday for about half the summer.

“They learn some of the routines and structure that define the place,” she said. “Kids come out of it with a sense of graduating from boot camp.”

Although the children’s tucked-in KIPP T-shirts were not exactly camouflage and their most powerful weapons were pencils and violins, the hallways and classrooms did seem a bit like boot camp, as children were drilled in math and literacy and grilled on sitting up straight, standing in single-file lines, and keeping quiet at lunchtime.

Despite abundant rules and the hour-plus of homework each student is promised every night, most children said they were glad to be at school. “It’s a better advantage for us,” Ricardo Welch, 12, said. His classmate, Damaris Negron, 12, said, “It helps us learn for the next level.” Tiara McFarquhar, 11, said, “I feel kind of sorry for them,” when asked about other city children who were home, doing whatever they desired. “Our teachers give us the best education they can,” she said. “They sacrifice for us. My elementary school teachers, they didn’t do that much for me.”

Even the youngest KIPP students said they were glad to be learning.

“I’m happy because I want to get a good education,” said fifth-grader Grace Marino, 9.

Her new classmate, Nia Louden, 10, said, “You have to make sacrifices when you’re young so you can have a good life when you grow up.”