Seventy-two Long Island school districts started classes Tuesday in the biggest opening day of the 2016-17 academic calendar — a year when many schools are celebrating the expansion or restoration of student services made possible by a general economic recovery.

The Middle Country district, for example, is bringing back regular art and music lessons that were cut 12 years ago from its kindergarten program. Plainview-Old Bethpage, which opens Wednesday, is adding an extra daily academic period to the high school schedule.

Kelly Zacher, a newly hired music teacher in Middle Country, started her school day by playing her guitar and singing a song that included the names of all of her kindergartners. The children moved on to making their own music with “boom whackers” — plastic tubes that they smacked against their palms to create a variety of notes, depending on the length of the tubes.

In another classroom, Karissa LaLima, a new art teacher, conducted a lesson in self-portraiture. Both teachers were working at the district’s Unity Drive PreKindergarten-Kindergarten Center in Centereach, which enrolls about 550 youngsters.

The Unity Drive school was celebrating its 60th anniversary. So LaLima asked her kindergartners to imagine what they would look like at age 60, then create pictures of themselves with the help of paper, glue, colored markers and cotton balls.

The assignment gave LaLima a chance to explain some basic class procedures — for example, how to snap a cap back on a marker and avoid leaks. She expects to move along quickly to more sophisticated lessons, such as introducing and interpreting the works of famous artists, including the 20th-century painters Piet Mondrian and Wassily Kandinsky.

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“They really do a lot of higher-level thinking,” LaLima said of students on that grade level, adding that eliciting thoughtful responses from 5-year-olds mostly is a matter of asking the right questions. “It’s really wild to see.”

Parents who brought their children to Unity Drive said they welcome the addition of art and music lessons taught by certified teachers, as well another new program in math literacy.

“She’s going to learn more,” said Juan Rivas, a Selden mechanic who accompanied his daughter, Jennifer, 5, to school.

Plainview-Old Bethpage is extending its high school schedule from eight to nine class periods a day — an important addition for students seeking to sign up for extra course electives. The expansion brings the school’s schedule in line with those of most others in the area.

“I’m excited,” said Lorna Lewis, the district’s superintendent, who explained that the nine-period schedule was a longtime goal. “We’ve been waiting on this for over 20 years.”

Islandwide, school officials said program restorations are largely the result of careful budgeting, helped by recent enrollment decreases that allow districts to save money on regular classes and use funds for other purposes.

Another plus, officials said, was this year’s $155 million infusion of state financial aid for the region’s schools, which included the return of more than $90 million cut during the recession-driven downturn.

At Elwood Middle School and Westhampton Beach Middle School, the first assignment for many students was getting to know each other.

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Twelve students in Christina Kerensky’s class at Elwood Middle School walked around with pink bingo cards, filling spaces by identifying students whose stories matched the squares: “Has lived in Elwood for their whole life,” “Has a pool or a boat,” “Was born outside of the United States,” “Likes the Yankees better than the Mets.”

Then, in another exercise, they split into groups to create five-pointed star patterns with a piece of rope. By the end of the games, they knew some of the other kids’ names.

“I liked the one with the rope,” said Emily Ferguson, 13, an eighth-grader. “I feel . . . like it’s teaching people to work together to come up with an end-product.”

The exercise, along with other playful activities and discussion for the day, was also a way for the school to help students break the ice and have a smooth start, teachers said.

Kerensky, one of the teachers who conceived the “Knights of the Round Table” program, said the aim was “to get them talking to each other” and “hopefully ease that first-day unsettling feeling.”

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Another teacher, Alessia Franco, who usually conducts classes in Italian, switched for the day to an exercise where everyone, including herself, had appointments scheduled to meet and chat with others in the classroom.

At one point, Franco talked with Nathaniel Petit, who told her he wants to play on the school’s football team. She encouraged him to sign up.

“I was feeling nervous” about the first day, the 12-year-old said later. “Conversation and talking to people helped me.”