Chicago strike to go into fifth day; no classes Friday A large group of public school teachers marches past John Marshall Metropolitan High School Wednesday on Chicago's West Side. Updated at 3:31 p.m.. ET: CHICAGO -- Classes for the nation's third-largest school district were canceled for Friday as the Chicago teachers set out to strike for a fifth day, according to NBCChicago.com. Negotiators trying to bring an end to the Chicago teachers' strike had said they were confident an agreement would be reached soon, but union leaders cautioned parents it was "highly unlikely" students would return to school Friday. Chicago Teachers Union president Karen Lewis said she hoped an agreement can be reached by the end of Thursday, the fourth day of the strike. Lewis told reporters she doubts teachers would be back in classrooms Friday, but said she's hoping for a Monday return. Oh, I'm praying, praying, praying. I'm on my knees for that, please," Lewis told NBC Chicago. Yes, I'm hoping for Monday. That would be good for us. Chicago Public Schools chief education adviser Barbara Byrd-Bennett was even more optimistic, saying she was trying to get students back in class by Friday. "The conversation was productive," Byrd-Bennett said on Thursday. There was steady and substantial movement on key issues around teacher evaluation and layoffs and recall. Chicago's teachers in the nation's third-largest school district went on strike Monday for the first time in 25 years in dispute of education reforms sought by Mayor Rahm Emanuel. "We made significant progress on the teacher evaluation side of the equation," Byrd-Bennett told NBC Chicago. Clearly we're remaining consistent with not wanting to lower the standards for our children. ... I think there were really good discussions. But Lewis said Thursday, there's still much work to be done. "We haven't even talked about the professional development side," she said. We want to make sure this is done right. Doing something fast is not the way to go. Haste makes waste. NBCChicago.com's Michelle Relerford and Lisa Balde contributed to this report, as did The Associated Press and Reuters.