In Ms. Davi’s school in California, a student missed the first three weeks of classes this year for a trip. Others have traveled to Las Vegas, Disneyland and Washington, D.C. The school’s policy allows these absences, so long as the administration is informed beforehand, but teachers are not obligated to put together work packets for children missing class for vacation.

“I tell the students, ‘We continue without you, so the responsibility is on you when you get back,’” Ms. Davi said, adding that classroom work and other assignments are online on Google Classroom. Whether or not a student will check in and keep up is “case by case.”

“There are some students who are intrinsically motivated as it is,” she said. “But then, there are students who are completely cut off. They come back and have no idea what’s going on.”