(CNN) -- Marathon talks to end the Chicago teachers' strike stalled again, meaning 300,000 students are missing a third day of classes Monday.
The Chicago Teachers Union and city officials negotiated through the weekend but couldn't reach a deal. So no one knows when 25,000 educators in the country's third-biggest school district will return to school.
"These negotiations must move more swiftly so that we can get students back into school as fast as possible," Mayor Lori Lightfoot said.
"Our team has been turning around thoughtful counteroffers at a rapid pace. We are hopeful that CTU will meet that pace ... so we can bring this process to a fair and responsible end."
The union's demands echo what teachers across the country are fighting for: smaller class sizes, more support staff, higher raises and more school funding.
But the mayor and Chicago Public Schools say it's just not realistic to fund everything the union wants.
"CPS is not flush with cash," the mayor said. "The fact is there is no more money. Period."
'Tragedies waiting to happen'
Chicago teachers say they're fighting for students who often face dire challenges.
About 75% of their students qualify for free or reduced lunch. In some neighborhoods, gangs and violence permeate the streets, forcing children to grapple with grief at a very young age.
Nine of 10 majority-black schools have no librarians, and there aren't enough bilingual teachers in a district that's "nearly half Latinx," the union said.
And many schools don't have a full-time nurse.
"There (are) just tragedies waiting to happen because we don't have enough staff in our schools," nurse Dennis Kosuth told CNN affiliate WLS.
Last year, Kosuth had to split his time among six schools.
"It was impossible for me to give the kind of care that I wanted to give to my students," he said.
This year, he's working at three different schools. "But I'm still just as busy."
Hiring more social workers, counselors, nurses, bilingual teachers and librarians is just part of of the union's demands.
Teachers also want smaller class sizes, higher pay for all school employees and more teacher prep time during the school day.
More than 41,000 Chicago elementary school students are trying to learn in classes with 30 students or more, the union said. Of those, 5,290 are in classes with at least 35 students.
And from the elementary to high school levels, CTU said, some classes have more than 40 students.
A bit of progress
Chicago Public Schools has offered to steadily raise teachers' salaries to an average of $97,757 by fiscal year 2024.
"We will also ensure every school has a full-time nurse by 2024," CPS said.
It said it would also commit another 200 social workers and special education case managers for the highest-need schools over the next three years.
CPS' latest offer would also raise the salaries of teachers' assistants, nurses and clerks every year for the next five years.
But the challenge isn't just funding those new positions -- it's finding enough quality applicants.
"Social workers, nurses, counselors, and other similar positions are hard to hire," the school district said. "The candidate pool is limited, and hiring is competitive."
Last month, the union asked for "CPS to hire more than 1,000 new employees by October 1, 2019, across several hard-to-find specialties," the school district said.
"The (union's) proposal also calls for hiring approximately 3,000 more employees over the next two years at a cost of more than $800 million. Even if CPS could realistically afford such a commitment, it would be nearly impossible to meet those hiring goals."
After lengthy negotiations Saturday, the teachers' union said both sides are getting closer to an agreement -- but sticking points remain.
"We have tentative agreements on eight different items -- two in particular, I think, are huge," CTU Vice President Stacy Davis Gates said.
"One goes with the pipeline for teachers of color," which could help reverse "the precipitous decline of black teachers," she said.
"The other one that's huge is that over the life of the contract, we effectively have a charter (school) moratorium."
While many parents have joined teachers on the picket lines, some oppose the strike.
"To me, it's a whole distraction and interruption to the school year," said Liam Boyd, the father of a fourth grader at Blaine Elementary School.
"I don't support the union. I think the school district and the city has been more fair this time and (are) trying to be more fair."
The union's president, Jesse Sharkey, said he has two children in the school district.
"We understand that a strike is a disruption to the parents of the city," Sharkey said. "It's worth a short-term disruption if that puts in place over the long-term the conditions that make education better in this city."