Scores on college admission tests for the Class of 2018 are sending warning signs about math achievement in the nation’s high schools.

Forty-nine percent of students in this year’s graduating class who took the SAT received a math score indicating they had a strong chance of earning at least a C in a college-level math class, according to data made public Thursday. That was significantly lower than on the reading and writing portion of the tests: 70 percent of SAT-takers reached a similar benchmark in that area.

Math readiness among some groups was far lower than the average — 23 percent for African Americans and 33 percent for Latino students.

Among those who took the ACT, the share showing readiness for college-level math fell to the lowest level in 14 years — 40 percent. That was down from a recent high of 46 percent, according to ACT data made public last week.

Taken together, the results point to a major challenge for educators.

“The negative trend in math readiness is a red flag for our country, given the growing importance of math and science skills in the increasingly tech-driven U.S. and global job market,” said Marten Roorda, chief executive of the nonprofit ACT, based in Iowa. “It is vital that we turn this trend around for the next generation and make sure students are learning the math skills they need for success in college and career.”

The SAT scores gave the fullest picture to date of results from the revised version of the test launched in 2016. About 2.14 million students in the Class of 2018 worldwide took it, including nearly 2 million in the United States. Those were record totals, said the nonprofit College Board, which owns the test and is based in New York. They showed the SAT has reclaimed its long-held position as the most widely used admission test for the first time in seven years.

The average score on the SAT was 1068 out of a maximum 1600, up slightly from the previous mark of 1060.

This year’s national average for the reading and writing section was 536 out of 800, and for math it was 531. (The two section scores combined don’t match 1068 because of rounding.)

Much of the growth in students taking the SAT occurred through an expansion of testing during school days. In the most recent academic year, 10 states covered the cost of the SAT in public schools, with no charge to students or parents. The District of Columbia also covered the cost. That was up from three states and the District in 2014-2015.

Most in the District class took the SAT — 4,985 in the Class of 2018. Their average score was 497 in reading and writing, and 480 in math, for a combined 977. About one-third in D.C. met the math benchmark for college readiness. Nearly half met the standard for reading and writing.

In Maryland, the average SAT scores were 545 in reading and writing, 535 in math and 1080 combined. In Virginia, they were 567 in reading and writing, 550 in math and 1117 combined.

Participation varies from one state to another, significantly influencing average scores and making comparisons difficult. Students from poor families tend to score lower, for a host of reasons, than those with affluent parents.

About 1.91 million U.S. students in the Class of 2018 took the ACT, which does not disclose international test participation. The average combined score was 20.8 out of a maximum 36, down from 21 last year.

The ACT is less widely used in the D.C. region than elsewhere. Average scores were 23.6 in the District, 22.5 in Maryland and 23.9 in Virginia.