After 15 months of unresolved negotiations, thousands of educators walked on Monday in the freezing cold – the city's first teachers' strike in 25 years. After a brief "period of reflection," the union said, both parties are heading to the negotiating table on Tuesday.

The big problem: Denver teachers want higher, stable base salaries, not the unpredictable bonuses their school district uses each year to make up for the low base salary.

"The retention of our teachers has completely disappeared," said John Haycraft, special education teacher. "We can not keep teachers from year to year."

More than 2,600 teachers missed school on the first day of the strike, said Denver Public Schools spokeswoman Anna Alejo. This represents about 56% of the teachers in the schools run by the district.

To compensate for this loss, approximately 1,400 central office staff and 400 substitute teachers are trying to replace the missing teachers.

Haycraft said it did not bother him to trouble the school district.

"I think they need to show us that they have made tough choices and major cuts," he said. "In a sense, make their lives a bit difficult – in the same way as for us."

But this strike also has heavy financial consequences. Alejo said, "We estimate it would cost more than $ 400,000," said Alejo.

This cost includes the salaries of substitute teachers, programs and strike materials, as well as the loss of tuition fees in the district's kindergartens, which are closed during the strike.

Denver Public Schools has made several offers to the Denver Classroom Teachers Association. But the union rejected all these offers.

What each side has put in place

Denver Public Schools states that it has proposed:

• $ 23 million in new funding next year for teachers' base salaries. (This would raise the average salary of a teacher from $ 55,000 to $ 61,000.)

• A total investment of $ 55 million over three years.

A new wave of teachers & # 39; the demonstrations are preparing from one ocean to the other

• Starting salary increase of $ 45,800 for new teachers.

• An additional investment of $ 2 million in base salary for teachers and specialized staff, which "would result from further painful cuts in our central departments, which we believe would amount to the removal of approximately 150 positions at the central office ".

• The elimination of performance bonuses for senior managers in the central office. "We would invest these funds directly in our highest need schools, with a proposed increase in the education promotion bonus in our schools with the highest poverty rates," said the district. school. "Our offer increases this incentive from $ 2,500 to $ 3,000."

But the union said it expects "a fair, competitive and transparent process." salary schedule which gives priority to the basic salary compared to complicated and unreliable bonuses. "

When will this strike end?

Nobody knows. But "we're hoping for a quick fix on all of this," said Rob Gould, the union's chief negotiator. "Our teachers want to be in classrooms with their children."

Some say that legislators retaliate after teachers. victories
The strike is the latest in a long line of protests from teachers spread across the country last year and continue to gain ground in 2019.
In some states, teachers have what they want. Other times, they do not have it. And in some states where teachers have won in their protests, some lawmakers are retaliating with new bills.

Denver public school superintendent Susana Cordova said the district was ready for talks on Tuesday and hoped the strike would be historic as soon as possible.

"It's a problem for our children not to have their teachers in class," she said. "So I want it done right now."

CNN's Holly Yan wrote to Atlanta and reported it to Sara Weisfeldt in Denver.