CHICAGO (CBS) — We’re just seven days from the strike date threatened by the Chicago Teachers Union.

One of the sticking points in negotiations so far: The CTU wants more nurses, counselors and librarians.

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And they want it written into a contract.

On Thursday, Chicago Public Schools CEO Janice Jackson said it’s not that simple.

“We have to deal with a shortage and pipeline issue. There is a shortage and so to codify that in a contract, we just don’t think that’s the appropriate place to go. We have put it in writing in this year’s operating budget,” Jackson said.

Then there’s the pay issue.

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In the current proposal, the city is offering teachers a 16% raise over a five-year contract. But teachers propose a 15% pay raise over three years. The teachers said it’s not just about money, arguing that many classes are overcrowded.

“Oversized kindergarten classrooms, 37 in a classroom, is detrimental to the safety, health and cognitive development of our students,” said Dr. Caprice Mitchell.

Doctor Jackson said it has offered a 10 million dollar package to help reduce that issue. But if both sides can’t come to an agreement, a strike will begin October 17.

And earlier Thursday morning, teachers at Passages Charter School in Edgewater announced they will strike on October 22. They want a salary increase, more services for students with limited English skills and protection for immigrant and refugee students.

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Passages is funded by CPS and has one of the highest percentage of refugee students in the district.