Montgomery County school officials have found no single cause to explain the district’s steep failure rates on high school math exams, but they are proposing a series of steps designed to help boost student performance and close the math achievement gap.

Superintendent Joshua P. Starr offered a plan last week following concerns that started more than a year ago when exam failure rates of 50 percent to 60 percent in some courses alarmed parents in the high-performing school system.

Starr’s plan includes measures to beef up math expertise at the elementary school level; reconsider policies about how students progress through math; add new diagnostic tools to help support struggling students; increase professional development; and start an online library of teacher and student resources.

The recommendations draw on a lengthy effort by a district-created math work group to examine the issues behind exam failures and what can be done to turn things around. The group’s report was issued as Starr released his recommendations.

“The final report indicates that, as we know, there is no single factor responsible for high rates of failure on math exams and therefore there will not be one single strategy to improve student performance,” Starr told school board members as he described his approach.

Montgomery’s widespread exam failure came to light last year when a leader of the Rockville Parent Teacher Student Association circulated figures showing that 62 percent of high school geometry students had flunked their final, as had 57 percent of those in Algebra 2. In all, more than half of 30,000 students taking seven math courses failed countywide exams.

District data showed that the problem had gone on quietly for years. But while many students failed their exams, most still passed their math courses.

In its report, the work group did not find problems with alignment between math exams and curriculum, as some had suspected, and the group said that the level of rigor on the exams was for the most part appropriate.

But the work group said there was a pattern of low marking-period grades among a majority of those who failed the exam: Between 80 percent and 90 percent of students who receive a D or an E in either marking period fail the semester-end final.

Black, Latino and special education students have been disproportionately affected by the exam failures, Starr said in a memo to the school board, “thus heightening the urgency to address this achievement gap.”

The work group made several recommendations, including compiling best practices to help students study throughout the semester and prepare for the exam, expanding professional development and clarifying the role of exams, especially amid changes in curriculum and accountability.

Surveys done as part of the effort showed that nearly 62 percent of high school students who participated said more review time with the teacher would help math performance. Asked about the cause of the low grades, more than a third said they didn’t think they had to study much. About the same percentage said they needed more help during the semester. Nearly half of teachers surveyed cited students studying as a problem, saying students choose not to adequately prepare for exams or don’t know how to study for a cumulative semester exam.

Many teachers have pointed out that students consult a grading chart as they decide how much they should study for exams. Exams in Montgomery are worth 25 percent of a course grade, and the chart shows, for example, that a student who earned Cs in both marking periods of a semester could fail the exam and still earn a C in the class.

The group recommended a review of the impact of the chart and grading practices on student motivation.

As the math work group met during the past year, the district’s 25 high schools created action plans to zero in on struggling students. But exam grades released after first-semester countywide finals did not show immediate progress.

Christopher Garran, associate superintendent for high schools, said the action plans would be useful in implementing Starr’s strategy. Garran noted successes such as more collaboration among math teachers, special education instructors and teachers of English for Speakers of Other Languages.

Starr recommended starting math success early by increasing the number of elementary school math coaches who work to help students struggling with the subject. This could happen over the next several budget cycles, he said.

He suggested reviewing policies that guide how students progress through math. Middle school students who earn a D or fail math courses are often moved on to the next course despite a lack of proficiency, Starr said.

“We know that kids who have not done well in middle school likely won’t do well in high school, and we’ve got to break that cycle,” Starr told the board last week.

In another change, Starr recommended supporting struggling students through new products and models of giving teachers “real-time information” about strengths, weaknesses and progress.

Professional development for teachers intended to help students struggling in math was another focus. Starr said the district pulled back on professional development amid economy-driven budget strains. “We need to reinvest,” he said.

Merry Eisner-Heidorn, a member of the math work group that issued the report and now a school board candidate, said Starr’s recommendations appear to make sense. But she also said they lack detail about measuring success.

“Without established metrics about how we’re going to judge our investments, I’m concerned we’re going to continue to invest and not get the results we need,” she said.