And as rhetoric and accusations came from both sides, mothers like Terrilyn Alexander scrambled to turn her family dining room into a classroom. Alexander and her husband are giving their three children four hours of schoolwork daily and say they can't help but resent it.
"What bothers me is the selfishness," Alexander told CNN affiliate WBBM. "The fact is, there should never be a reason to keep children out of school."
Talks ended Tuesday night with neither side expressing optimism that an agreement was near.
"This was silly season," board President David Vitale told reporters after emerging from more than 10 hours of talks. "It is time for us to get serious."
Vitale said the board had presented the teachers union with a "comprehensive proposal" and would resume negotiating only after "we receive a written response or a comprehensive proposal of their own."
But Barbara Byrd Bennett, interim chief education officer, said the negotiating would continue Wednesday, whatever happens. "Our team will be back here tomorrow," she said.
Chicago Teachers Union Vice President Jesse Sharkey said the day's discussions had centered on teacher evaluation and that "some substantial movement" had been made, but not enough.
"I don't want to get in the weeds, but I'd say we moved more than they did today," he said.
The board proposal would leave some 28% of teachers in danger of dismissal within two years, he said, calling that "an insult to our profession."
"They basically dug in their heels and said if we didn't give them a comprehensive proposal, we didn't have anything to talk about," Sharkey said.
The negotiations ended after thousands of striking teachers had spent much of the day massed outside the Chicago public school system's headquarters.
Carrying signs, they chanted and marched through the streets in an expression of solidarity in their fight against the school board.
"We have a considerable way to go," union spokeswoman Stephanie Gadlin said in a news release. "This is a fact they cannot deny."
Of 49 points in the contract offer, the union has agreed to just six, she said.
"We are fighting for our students; we are fighting for education justice," she said.
"This was a strike of choice. And it's the wrong choice for the children," he told reporters.
After five months of negotiations, "we're down to two issues," he said. The sticking points are teacher evaluations and provisions dealing with jobs for laid-off teachers, said Emanuel.
The talks could have continued without a strike, which was "totally avoidable, totally unnecessary," Emanuel said.
Late in the afternoon Tuesday, U.S. Education Secretary Arne Duncan issued a statement expressing confidence "that both sides have the best interests of the students at heart, and that they can collaborate at the bargaining table -- as teachers and school districts have done all over the country -- to reach a solution that puts kids first."
The union, which represents nearly 30,000 teachers and support staff in the nation's third-largest school district, called the strike Sunday night. The union said the two sides had been close to a deal on pay, but far apart on teacher evaluations, benefits and other issues.
As many as 6,000 teachers could lose their jobs under the evaluation system, said union President Karen Lewis, who called the system "unacceptable." The mayor's office, the city and school officials have questioned that job-loss figure.
The median base salary for Chicago public schools teachers in 2011 was $67,974, according to the system's annual financial report.
And as the teacher strike reached began its third day Wednesday, some student athletes were complaining.
Because of the strike school sports programs were closed and games would be canceled, according to CNN affiliate WGN.
Demetrius Harris, a senior football player at Roberto Clemente Community Academy High School, said a prolonged strike could dwindle his choices for college.
"It's really affecting our senior year," Harris told the affiliate. "I mean, we have six or seven more games left and we're trying to play as much as we can. We don't have another shot at this. It's our last year, it's our last time to prove to colleges and recruiters that we can go out and play."
CNN's Amanda Watts, Lateef Mungin, Josh Levs, Michael Pearson, Casey Wian, Greg Botelho, Ted Rowlands and Greg Morrison contributed to this report.
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