Every three years, the OECD, in the PISA assessment, studies 15-year-olds around the world to measure performance in reading, mathematics, and science. The results of the 2012 PISA assessment, which had a particular focus on mathematics, just came out and the United States does not fare well: "Among the 34 OECD countries, the United States performed below average in mathematics in 2012 and is ranked 26th." I worry not so much about the rank, but about the low absolute level of proficiency to get this rank.
The U.S. students' particular strengths and weaknesses are even more distressing:
Students in the United States have particular strengths in cognitively less-demanding mathematical skills and abilities, such as extracting single values from diagrams or handling well-structured formulae. They have particular weaknesses in items with higher cognitive demands, such as taking real-world situations, translating them into mathematical terms, and interpreting mathematical aspects in real-world problems.