WASHINGTON (AP) — The nation's high school seniors are slipping in math and failing to make progress in reading, with just one-third of the 12th graders ready for the academic challenges of college. Education Secretary John B. King, Jr., says schools have undergone "some of the most significant changes in decades" as teachers retool their classroom practices to adapt to new and higher standards. Since 2009, more than 40 states have adopted the Common Core learning standards, which outline skills students should learn and know in math and reading by the end of each grade. Peggy Carr, acting commissioner of the National Center for Education Statistics, which administers the test, said the report suggests a pattern in reading scores that needs a closer look. The report estimates about 37 percent of students, for both reading and math, scored well enough to be considered likely to possess the knowledge and skills to be academically prepared for college-level work.