BRIDGEPORT — It’s a math equation that in recent years the city school district has answered with longtime substitute teachers.

Not this year at Central High School.

The district will pay 10 city math teachers to take on a sixth class, at least until it can hire someone certified to fill the two vacancies that exist at the city’s largest comprehensive high school.

“You know what, when you are talking about math, you can’t play around,” said Hermino Planas, who in addition to being an executive director of elementary education is still in charge of math for the district. “I would like a full-fledged teacher in front of the class. It’s better than babysitting.”

The city school board last week agreed to a memorandum of understanding with the Bridgeport Education Association for the 2019-20 school year that will give teachers a one-sixth boost in salary for taking on a sixth teaching period.

For a teacher making $52,070 a year, it would mean an $8,678 addition to their annual compensation.

Central Principal Eric Graf said the two math vacancies this year were due to retirements. Efforts to replace them through normal channels failed.

High school math is one of the top 10 shortage areas designated by the state Department of Education.

“The Fairfield Teacher's Agency, for example, did not even have a math candidate to send me for an interview,” Graf said. “I did not want our students to go through the year without a certified math person teaching them. ... It did not seem likely that we would find a math teacher any time soon.”

Years ago, Graf said, he remembered teachers being paid to take on a sixth class in an emergency situation. Acting Schools Superintendent Michael Testani was agreeable to the idea and so were most of Central’s 13 math teachers, Graf said.

Planas said where possible, teachers are taking on a course they are already teaching so it does not require an extra prep period. Most teachers at the comprehensive high schools have seven periods a day, five classes, one prep period and one duty period, where they could be called on to monitor a hallway or the cafeteria. The additional teaching class will take place of the duty period.

While the practice of paying teachers extra to take on an additional class has not been common in Bridgeport, it is used by a good many other districts, officials said.

“Many contracts make provisions for these instances,” said Nancy Andrews, a Connecticut Education Association spokeswoman.

State officials say the practice is used for both shortage and non-shortage areas when student numbers and course sections require.

“Our Talent Office said it happens all over the state,” said Peter Yazbak, a state Department of Education spokesman.

It is unclear why Bridgeport hasn’t turned to the practice sooner. There have been times when students have gone the entire year with long-term subs in critical subject areas like math rather than a certified teacher.

As of last week, the state had 4,425 certified 7-12 grade math teachers. Math is also a subject a good number of students in the state lag behind. On newly released SAT scores administered by the state to high school juniors, just 41 percent statewide scored at or above what is considered grade level. In Bridgeport, 12.6 percent of students reached or exceeded grade level.

Planas said the teacher solution being employeed at Central is not needed at either Harding or Bassick. Both schools this year have all teaching positions filled. There is one math vacancy at Fairchild Wheeler, an interdistrict campus of three schools.

Because Fairchild has a block schedule with longer class periods, it can’t use existing staff to fill the vacancy, officials said.

Planas said the district continues to look for teachers to fill that vacancy, plus the two math positions at Central.

In the meantime, Graf said he has told the math teachers taking on extra classes to let him know if they need additional support.; twitter/lclambeck