The city’s high-school students were stumped by the Common Core algebra exam this year.

Fueled by poor algebra-test scores, only 55 percent of kids passed the math exams, down 6 points from 2014, according to data released on Thursday.

In the rest of the state, overall math scores were down by even more, 7 points.

Teachers and kids said the algebra exam, which ninth-graders must pass to graduate, was too hard.

Mayor de Blasio and Schools Chancellor Carmen Fariña last month unveiled a plan to increase access to Algebra instruction.

“We expressed concern surrounding the Algebra exam, and are encouraged that the state formed a committee . . . to address technical and policy issues surrounding the new Common Core exams,” said city Department of Education spokeswoman Devora Kaye.