Southern Maryland students at nearly all grade levels improved their performance in reading and math on statewide tests, according to results released this week.

The most significant gains in Charles County were made in fourth-grade reading and sixth-grade math, in part because of after-school and summer programs, officials said.

The portion of students reaching proficient or advanced in fourth-grade reading increased from 72.3 percent to 80.4 percent this year. In sixth-grade math, 62.2 percent of students scored proficient or above, compared with 53.2 percent last year.

"Middle school math has been a tough area for the whole state, so we're real excited about that,'' said John H. Cox, assistant superintendent for instruction for the Charles County public schools.

Students took the Maryland School Assessment tests in March. The results reported Tuesday measure achievement in reading and math by showing what percentage of elementary and middle school students performed at basic, proficient or advanced levels.

The scores are the most significant factor in determining whether the state's 24 public school systems and roughly 1,050 elementary and middle schools are meeting annual performance standards established under the 2002 No Child Left Behind law.

In the 16,500-student St. Mary's school system, the largest percentage increases over the past year for students scoring proficient or better came among those enrolled in the special education program. In the reading category for fourth-graders in special education, for example, the portion of those who were proficient or advanced went from 39.5 percent in 2004 to 63.4 percent this year, an increase of 23.9 percentage points.

In all but one category, eighth-grade math, students in St. Mary's scored better than the statewide averages.

"We are absolutely moving in the right direction," said interim Superintendent Lorraine Fulton. She attributed the increases to the school system's focus on finding out how much each student knows and its commitment to the voluntary state curriculum. Last year, for example, the school system began using a state-recommended mathematics program called "Investigations" to teach basic math skills and problem solving to students in kindergarten through third grade, Fulton said.

In general, older St. Mary's County students scored proficient or advanced in math at lower rates. Nearly 80 percent of third-graders scored in those categories on the math test, but just 46 percent of eighth-graders did. In reading, the numbers tended to stay more consistent through the grades: 75.9 percent of third-graders were proficient or better this year; the figure was 73 percent for eighth-graders.

Scores decreased slightly in a couple of areas, including third-grade special education math (by 2 percentage points) and seventh-grade reading (by 1.3 percentage points). School officials said the drop at the seventh-grade level was seen in several counties.

"That is a trend throughout the state. I truly don't know if it's a reflection of the test itself or how we are applying the curriculum," Fulton said. "That's something we will be analyzing."

Seventh-grade reading also was the one exception to the uptick in Charles County. The portion of students reaching proficient or better dropped slightly, from 69.3 percent to 68.6 percent this year.

"I would of course like to see a plus,'' Cox said. "But it's not an alarm status.''

In Calvert County, which has about 18,000 students, school officials hailed increases in all grade levels and both subjects. They cited a team-teaching experiment at Northern Middle School for increasing the scores of sixth-grade students. This year, 93.9 percent of sixth-graders at that school reached the proficient level or better in reading, compared with 85.7 percent last year.

"It was dramatic," said Carol Reid, the assistant superintendent in Calvert County.

Some of the biggest gains in Calvert were in eighth-grade math, in which 53 percent reached proficient or above, compared with 47.3 percent last year. The school district purchased new textbooks that are more closely aligned with the state curriculum and with high school algebra and geometry courses.

Mark Wilding, the secondary school math supervisor, introduced what is known as the math "problem of the week," which helps students understand how they will be graded. He created mock versions of the state tests to prepare students throughout the year.

"We're trying to diagnose what our students' weaknesses are before they sit for the final exam in March,'' he said.

Under the federal No Child Left Behind Act, all students must be at least proficient in math and reading by 2014. School officials said they expect the federal ratings to be released next week. Schools that fail to meet the benchmarks can be placed on watch lists and eventually face other penalties if scores do not improve. The law also requires schools to track performance according to income and race.

In Charles County, where 47 percent of the school district's 26,026 students are black, the achievement gap with white students has narrowed. In 2003, for instance, the gap between third-grade black and white students who reached the proficient level in reading was 24.9 percentage points. This year, that gap was 12.5 percentage points.

In St. Mary's County, black students make up about 20 percent of the enrollment. Officials said they were happy that the achievement gap between white and black students was closing, but a disparity remains, according to the test data. On the eighth-grade math test, 50.1 percent of white students scored proficient or better, compared with 24.2 percent of black students.

St. Mary's interim Superintendent Lorraine Fulton said scores are "moving in the right direction."