CHICAGO (CBS) — The Chicago Teachers Union took issue with class sizes Wednesday, while Chicago Public Schools officials said they are working to combat the problem – as the days count down to a possible teachers’ strike.

The CTU has set a strike deadline of Thursday, Oct. 17 to reach a tentative agreement on a new contract.

CTU leaders have said the city’s current proposal isn’t good enough for its 25,000 members. The district has offered a total 16 percent pay raise over a five-year contract, while the teachers have proposed a 15 percent pay raise over a shorter three-year deal. The dispute over pay raises aside, the union wants CPS to hire more social workers, counselors, nurses, and librarians.

CPS Chief Executive Officer Dr. Janice Jackson said the district already has committed to a five-year plan to hire hundreds of nurses, social workers, and case managers, and has budgeted millions of dollars this school year to hire 95 new staffers “as a down payment on that commitment.”

However, the union has demanded that the mayor and CPS put a commitment to hire additional nurses, librarians, social workers, and counselors in writing in the contract, not simply budget for them, claiming the district has broken staffing promises in the past.

The teachers also want more teacher prep time and smaller class sizes. At a news conference Wednesday at Simeon Career Academy, 8147 S. Vincennes Ave., the teachers focused on what they said were the problems with class sizes as they are.

“I currently have 172 students – my largest class being 37; my smallest, if you could call, it that is 32,” said Simeon math teacher Maria Aguirre. “Being a math teacher, I measured the square feet of my room. My room only allows for 29 students. Therefore 37, they’re in very close proximity, creating distractions, disciplinary problems and hazards. As I walk around to check their work, I often trip over book bags. I have barely enough space to walk around those desks. We have no room to move students around. I cannot help struggling students, I cannot group them to help them in small group instructions because my room does not allow for that.”

“Some classes have 42 students, some have 32-33 students. In my classroom, my first grade classroom I have 34 students. Out of those 34 students, I have 12 that don’t know their letters, their letter sounds, their kindergarten sight words. I do have some that can read, but it’s a wide range of abilities,” added first grade teacher Gloria Torres. “How can I teach them the way that I need to teach them if the classes are overcrowded?”

Simeon sophomore Neryssa Scott said she has had trouble learning because there are too many students in the classes.

“I have a class, my eighth period class – I have trigonometry. And we have about 37 students in our class and that is a shame because today I needed help and I couldn’t get the help I needed because she had to keep going around the classroom, trying to tell them to calm down, or help other students where she couldn’t help me. I understand that might sound selfish but it’s not. I need the education that I want. I’m trying to pass but I can’t do that because there’s only one teacher against 40 other students,” she said. “That is a shame. And I need that fixed now so I can get the education I want to receive.”

In response to the complaints CPS spokeswoman Emily Bolton said, “The district has made significant progress to minimize classroom overcrowding in the vast majority of schools across the City, and our offer makes a $10 million investment to provide 200 staff members to support classrooms experiencing overcrowding.”

CPS said the district has made significant progress on overcrowded classrooms and said last school year, the average elementary school class had 25.2 students.

CPS also said the existing collective bargaining agreement also stipulates class sizes of 28 for kindergarten and primary students and 31 for intermediate and upper grade students – and said the vast majority classrooms are below that level as it is.

CPS added that the existing collective bargaining agreement currently involves a class size monitoring panel with CTU members, and also requires that kindergarten through second-grade classrooms with 32 or more students are assigned more support staff. Under the new contract offer, that would expand to third-grade classrooms, CPS said.

If a strike goes ahead, it would be the second teachers’ strike in seven years. Before 2012, there had not been a teachers’ strike in 25 years.