As all schoolchildren know, water freezes to solid, barren, cracked ice at 32 degrees Fahrenheit. So maybe it is more than a mere coincidence that 32 percent of U.S. public and private-school students in the class of 2011 are deemed proficient in mathematics, placing the United States 32nd among the 65 nations that participated in the latest international tests administered by the Organization for Economic Cooperation and Development (OECD). The United States ranks between Portugal and Italy and far behind South Korea, Finland, Canada, and the Netherlands, to say nothing of the city of Shanghai, with its 75 percent proficiency rate.