But the southern states of Alabama, Louisiana and Mississippi, and schools in the troubled US capital of Washington DC, have an achievement level close to Jordan, one of the lowest-rated nations in the world, says a new report.
The National Science Foundation's seven-year survey of science and mathematics achievement at all levels of American education shows elementary schools are devoting more time to the subjects.
Scores improved overall, but huge disparities between regions and ethnic groups remained, it said. The top-ranked states were Minnesota and neighbouring North Dakota. The third was Maine.
Numbers attending the highly selective preparatory classes, which train students for the competitive entrance exams to the grandes ecoles, have risen sharply this year after three years of falling rolls, according to an education ministry report.
The elite ecoles specialise in science, engineering, medicine, business studies, political science and training for the civil service.
More than 70,000 post-lycee students are enrolled in classes preparatoires, nearly 5,000 more than last year. The sudden reversal is due, says the report, to last summer's high baccalaureat pass rate and radical reforms to the structure and curriculum of the scientific prepas. These also extended to two years the economic and commercial classes, which registered the biggest increases.
Nearly 29,000 women attend the classes, representing 38 per cent of students, the same proportion as last year.