Mayor de Blasio's mantra for the public schools is “Equity and Excellence.” But this fall, how often a student will get to attend in-person classes will depend on how crowded -- or overcrowded -- her school is.

"The system is inherently inequitable,” said Leonie Haimson, executive director of the group Class Size Matters. “Across the city there’s a huge variety of class sizes, so most schools manage to keep classes at 20 or 25, and other schools, all their classes are at 30 or 34 or more."

To keep students a safe distance from each other, no classroom in the new school year can have more than 12 students, and all desks must be six feet apart. Many schools will be able to host half their children, on alternating days. One week, a student will attend in person twice; the next week, three times.

"Some schools that are so overcrowded normally that they're going to have to do, you know, three shifts,” de Blasio said. “On some weeks a kid might only be in school once a week, and other weeks twice a week. That's for the most overcrowded schools."

Actually, the outlook is even worse at the most overcrowded schools.

Arthur Goldstein is a teacher and union chapter leader at Francis Lewis High School in Queens. He says students at some schools, including his, likely will be divided into five groups. 

"We are very overcrowded. That would mean that to open the school it would mean my students would see me one of five days a week,” Goldstein said.

In 2019, the school had 4,492 students. That's 205 percent of its target capacity of 2,188. Goldstein recently walked the building with his principal.

"He set up a model room in which there were 10 desks. Just to show you how little they thought this out, if we were to take 25 desks out of each classroom, we don’t even know where we would put the desks,” Goldstein said.

The city has said it will search for extra space for students. At Francis Lewis, a long-promised annex is years away from completion. 

"We are the largest school in Queens, we are the most overcrowded in the city. At least for my part, I try to make us heard, and we are ignored in these plans,” Goldstein said. “We are an outlier, but nonetheless we deserve consideration.”

An Education Department spokeswoman says it is working with a small group of these outlier schools, but that their needs won't be entirely clear until after they find out how many students will opt for full-time remote learning.