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.

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.

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.

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