The highest percentage of New York City fourth-graders passed the state math exam last year, Mayor Bloomberg and his schools chancellor, Joel Klein, announced yesterday, but eighth graders were not so successful.

The test results released yesterday by the state Board of Regents show 77.4% of the city’s fourth-graders met state standards, a 9.3% increase from the previous year and a 25% increase since the mayor took control of the schools in 2002.

The mayor, who has repeatedly urged voters to judge him on his attempts to remake the city school system, touted his reforms yesterday at P.S. 40 in Bedford-Stuyvesant, Brooklyn, where the number of fourth-graders who passed the exam almost doubled.

“This should put a smile on the face of every parent,” Mr. Bloomberg said. “The era of when year-in, year-out stagnant levels of classroom performance was the norm are over.” The overall results were a mixed bag, however, with the number of eighth-graders meeting state standards declining 1.6 percentage points, to 40.8%. A year ago, their scores rose 8%.

The mayor blamed the eighth-grade scores on a school system that promoted students “without any standards” and said the recent move to end social promotion of seventh-graders would bolster future results.

“These are kids who didn’t get an education in elementary school,” he said when asked about the almost 60% of eighth graders who failed to meet state standards. “That is why we have been willing to go and devote resources to the middle school. Ending social promotion in the seventh grade and $40 million for intervention programs right now is exactly what we have to do.”

Fourth-grade math scores saw the sharpest leap in Region 5, which is located in Brooklyn and Queens, with 80.3% of students hitting state levels, up from 66.4% the year before, the Department of Education said.

The unions for principals and teachers, both of which are in heated contract battles with the Bloomberg administration, lashed out at the mayor for taking too much credit for rising scores.

“This mayor and chancellor dare to claim their reforms are proving successful, but they are merely taking credit for the hard work of our principals, assistant principals, and their staffs,” the principals’ union president, Jill Levy, said in a statement.

The United Federation of Teachers, which attracted a slew of politicians to its rally on the steps of City Hall yesterday to pressure the mayor back to the bargaining table, voted this week to either hold a strike authorization vote or endorse the mayor’s Democratic opponent if a settlement is not reached by early October. The opponent, Fernando Ferrer, used yesterday’s scores to fuel his campaign.

“How much more evidence do we need that Mike Bloomberg’s obsessive focus on test scores isn’t working? Almost 60% of New York City’s eighth graders fail to pass state level math tests,” Mr. Ferrer said. “Bloomberg has ignored the dropout crisis in our schools – one that leaves half our kids behind – in order to focus on test scores, a strategy that’s clearly not serving anyone well.”

A Quinnipiac University poll released yesterday found that the level of dissatisfaction with city schools among voters has dropped to 66%.That is down from levels that ranged between 71% and 78% over the past three years.