UPDATED 09/08/12 5:39 p.m.

CHICAGO (CBS) — Negotiations between teachers and the Chicago Public Schools resumed on Saturday, in hopes of averting a Chicago teachers’ strike that could begin next week.

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As CBS 2’s Suzanne Le Mignot and WBBM Newsradio’s Bob Roberts report, the union has opened a strike headquarters at Teamsters City, at 1642 W. Van Buren St. on the Near West Side.

LISTEN: WBBM Newsradio’s Bob Roberts reports

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With union staff handing teachers red Chicago Teachers Union T-shirts, strike signs, and a bulletin with suggested picket line chances to backdrop, union vice president Jesse Sharkey says teachers continue to be disappointed at the table.

“We were told, we were very much hoping that yesterday we would get an offer that would really begin to bridge that gap,” Sharkey said. “The offer they came back with was disappointing, to say the least, and frankly, there’s not enough pieces of the puzzle there yet to make a picture. It’s not sufficient.”

Sharkey said the union is willing to remain at the table around the clock this weekend to try to avert a walkout.

At a news conference Saturday afternoon, union leaders were outlining all the formal preparations for a strike.

The union said all teachers will report to picket lines at 6:30 a.m. Monday. At 8 a.m., the strike coordinator may shift some teachers to picket at 144 holding centers — schools that will be kept open for part of the day and provide breakfast and lunch to schoolchildren.

The union will photograph any teachers who cross the picket line.

At 3:30 p.m. Monday, all union members must attend a massive demonstration at Chicago Public Schools headquarters, 125 S. Clark St. On Tuesday, they will picket at the holding centers.

Teachers can pick up signs from 5 a.m. to 3 p.m. at the union headquarters, at 1642 W. Van Buren St.

CBS 2’s Mike Puccinelli reports the teachers also have been handed bulletins with scripts for chants they will shout during the picket. One of them goes, “Rahm, Brizard, we’re no fools, we won’t let you ruin our schools!”

A strike hotline has also been set up, at (312) 329-6209.

Meanwhile, supporters came out Saturday to tell why they back the union.

None of the arguments were new, but this time, the supporters spoke against a backdrop of union staff handing teachers picket signs.

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Becky Malone of the 19th Ward Parents’ Organization ridiculed the Chicago Board of Education’s plan to open 144 holding centers for four hours each weekday as $25 million wasted on babysitting when far more critical needs go unmet.

“There’s no funding for the arts, for drama, world languages and hands-on learning opportunities we were promised,” she said. “Even if some of these programs were added this year, the board has depleted any funds to be used in the future (from its rainy-day fund). So there’s no long-term sustainability for a longer school day.”

Malone said up-to-date textbooks for students would be a start.

Erica Clark of the group Parents for Teachers said she sees it as an issue of disrespect, and the damage it has done. She said students don’t learn because classes are too large, shootings spiral out of control because the school board has gutted its counseling staff, and said innovation is stunted by an administration that tells parents and others with ideas to simply “shut up.”

“It’s about more than money,” she said.

Two students from Roosevelt High School agreed, saying that in the end, all of the skimping shortchanges students.

The head of the Service Employees International Union Local 1 says his thirty thousand Chicago members will be showing their support on their sleeves.

“Our members who have to work and go in, they will be wearing red kerchiefs on their arms, or their heads, or their necks. That’s to celebrate the teachers’ struggle, and that’s to signify that we stand with the teachers 100 percent,” said SEIU Local 1 President Tom Balanoff.

But the Rev. Jesse Jackson on Saturday advised teachers and CPS officials to do whatever it takes to reach an agreement.

“Lock the door, and stay in the room until smoke comes out the window. Don’t leave until the matter is resolved,” Jackson said. “Do not risk disrupting the city, county and state because somebody cannot work out some angle. Work it out. Don’t give up. Work it out.”

On Friday, Chicago School Board President David Vitale initially said the two sides had “closed the gap fairly significantly” and expressed confidence that students in the Chicago Public Schools system would be in class on Monday.

But even though CPS expressed optimism, the district still advised parents to plan for a strike.

CPS plans to open the 144 “holding center” schools between 8:30 a.m. and 12:30 p.m. if there is a strike. CPS will continue to make automated calls to parents during the weekend.

But the district will not provide transportation to the schools that will be open, and after-school programs will be canceled

The CTU’s House of Delegates voted last week to strike as soon as 12:01 a.m. Monday if a contract is not worked out. The tone of public statements from both sides of the negotiating table had been cordial the last few days, but Lewis said an expected counter-offer from CPS did not materialize Friday.

The two sides have said they are still trying to resolve disagreements over wage levels, teacher evaluations and how teachers are recalled for work after layoffs, among other issues. Lewis would not provide specifics at the Friday news conference.

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A strike by CTU members would displace 30,000 teachers, counselors and other educational professions and deny classroom instruction to 350,000 students across the city.

Suzanne Le Mignot