CHICAGO (CBS) — As tensions mount over stalled contract negotiations keeping kids out of school, and putting student athletes at risk of missing state playoffs, the Chicago Public Schools said it is cancelling classes again on Friday, the seventh missed school day due to the strike.

That matches the length of the 2012 teachers’ strike, when the Chicago Teachers Union walked off the job for nine days — including seven school days — after reaching a tentative deal with the CPS administration under then-mayor Rahm Emanuel.

Negotiators were back at the table on Thursday, but CPS said the union’s House of Delegates had not scheduled a vote to end the strike as of 4 p.m., so the district could not hold classes on Friday.

On Thursday evening, CTU Chief of Staff Jennifer Johnson said it had been a “good day” at the bargaining table.

“We had members picketing back and forth at their schools; members getting creative, getting together, and then canvassing in their community, talking to parents, talking to the people that most understand our struggle here and that most understand that if we win, their students win,” Johnson said.

She said the bargaining team expects to be back at the table on Friday morning, and afterward, striking teachers will gather at Buckingham Fountain.

The two sides are still not in agreement on class size, staffing, and pay for paraprofessionals, Johnson said.

She said no meeting has been scheduled for the CTU House of Delegates, which would be required for any end to the strike.

CPS Chief Education Officer LaTanya McDade also said Thursday night that CPS had had a “productive” day and was encouraged by the progress being made. CPS officials declined to talk about what key issues were discussed Thursday so as not to hinder the progress.

On Wednesday, thousands of CTU members and their supporters flooded streets downtown for a rally while Mayor Lori Lightfoot was presenting her city budget address.

Even before CPS announced the cancellation of classes on Friday, CTU and school support workers represented by SEIU Local 73 had scheduled a rally for Saturday at Union Park, hosted by the Illinois Federation of Teachers, an apparent signal the union wasn’t expecting a deal before the weekend.

“As the strike goes into its second week, it is time to show that Chicago is a Union Town and support the efforts of these courageous workers with solidarity,” the Illinois Federation of Teachers wrote in a Facebook event page for the rally.

The union and CPS leadership continue to blame each other for the slow progress of contract talks.

“Every day that goes by, there’s another cost to our young people, our students, and their families; and we’re just not seeing the kind of progress that we need to from CTU,” Mayor Lori Lightfoot said Thursday morning.

CTU President Jesse Sharkey, however, said the mayor must bring more resources to the table in order to reach a settlement.

“We’re trying to put together a puzzle in order to end this strike, but we don’t have enough pieces on the table in order to complete the puzzle. The mayor still has a handful of pieces in her pocket,” Sharkey said. “Until she takes the pieces of the puzzle out of her pocket and puts them on the table, we’re not going to solve the puzzle, we’re not going to complete the picture, and those pieces amount to resources.”

The mayor has repeatedly said CPS does not have any more money than it already has put on the table to meet the union’s demands for pay, class sizes, and staffing.