CHARLESTON, W.Va. — The West Virginia legislature may have given striking teachers what they wanted — by accident.

The state Senate thought it had approved a bill on Saturday night that decreased proposed raises for striking teachers from 5% to 4% — a move that infuriated the teachers’ unions. About 20,000 teachers have been on strike for seven days, keeping 300,000 students out of the classroom.

But something went wrong.

A House version of the bill had somehow been entered into the Senate voting system, said state Sens. Roman Prezioso and Mike Woelfel. Members of the Senate didn’t notice the switch and the Senate ended up voting to give the teachers what they wanted — a 5% raise, Prezioso and Mike Woelfel said.

Members of the House discovered what happened when they officially received the bill, the two senators said. The House had approved the bill with the higher pay raise earlier in the week.

The Senate went back into chambers late Saturday and tried to figure out how to reverse the situation, but it was unclear if there were enough votes to do so, and if the parliamentary regulations would allow it.

Teachers will not go back to work without a 5% raise, Dale Lee, president of the West Virginia Education Association, said earlier in the day. The WVEA is one of three organizations representing the teachers.

Senate President Mitch Carmichael and other Republican legislators maintain the state cannot afford raises that would end the walkout by some of the lowest-paid educators in the country.

But supporters of the teachers said the raise was needed.

“We’re being penny wise and pound foolish,” state Sen. Ron Stollings said on the Senate floor. “We need to invest in education.”

The Senate changed the rules to allow three readings of the bill Saturday night. The bill was scheduled to move to the state House, but it was unclear when that would happen.

Earlier in the day, opponents and proponents of the higher pay raise had debated whether the money could be found.

Prezioso said a difference of one percent amounted to $13 million that could be secured from other agencies.

But Republican Sen. Gregory Boso, who proposed the 4% raise, was skeptical.

“For numbers to appear out of a meeting and show up on our desks saying all of sudden the numbers are there … as far as I’m concerned it’s about this worthless,” he said. He put his trash can on his desk, crumbled paper and dropped it in.

Sen. Charles Trump, a supporter of the 4% raise, said it will provide about $1,600 more to each teacher.

“We took our time — this body was deliberate with it,” he said. “The people of West Virginia expect us to do what is right. This is right.”

Boos rained down from gallery, where an overflow crowd of teachers and supporters watched a livestream from the Senate committee room.

Democratic Sen. Corey Palumbo said amending the proposed raise will likely prolong a strike that has already caused students to miss seven school days.

“We’ve got to end this. I think we pass this bill as is and get our kids back in school Monday,” he said, drawing applause from teachers and supporters in the gallery.

A continuation of the impasse this weekend would mean the battle for better benefits and higher pay could keep schools closed Monday, and possibly, through next week.

The bill proposes a 5% pay hike for teachers in the first year — more than the 4% total raise (spaced over three years) the Legislature initially passed.

The deal did not include an immediate fix to the state health insurance plan, the Public Employees Insurance Agency, or PEIA, which employees say requires them to pay premiums that are too high. The status of PEIA was a major reason for the strike, according to educators.

The bill also covers a pay raise for state police.

The teachers are eager to return to work but need more than a promise by the Legislature, Joe White, executive director of the West Virginia School Service Personnel Association, told CNN.

“What people have got to understand is that this is not something that has happened overnight,” he said Friday.

“This is something that has accumulated over the years. And (teachers and service personnel have) been lied to. And the trust factor, right now, is kind of slim. … What we’d like to see is things go back to normal, and they live up to an agreement and we move forward.”

Legislators, however, remain unsure about the financing.

The hike proposed in the bill hinges on new projected state revenue numbers that the governor announced earlier this week.

Carmichael has said he finds the projections hard to believe and wants to examine them more closely.

“We are absolutely bound by our duty to evaluate that with a fine-tooth comb,” he said. “We’re very skeptical.”

The proposed deal also called for the creation of a task force to address union concerns over the public employees insurance program.

Justice appointed the first members of the task force Friday and announced they will meet for the first time on March 13.

Teachers and service personnel have been on strike since February 22, shutting down public schools across the state for seven school days.

Educators, school staff and their supporters have descended on the state Capitol, holding daily rallies outside legislative chambers where they chant “55 United,” a reference to West Virginia’s 55 counties. Local pickets have gone up across the state as well.