PISA International Mathematics Performance Comparisons.. USA needs metric.static.guim.co.uk/sys-images/Guardian/Pix/pictures/2013/12/5/1386241291926/PISAFULLLITERACYWEB.png
PISA 2012 managed by ACER* for the Organisation for Economic Cooperation and Development (OECD) measured the mathematical, scientific and reading literacy of around 510 000 students across 65 participating countries and economies, including 34 OECD countries and 31 partner countries or economies.
Happy reading! Jonathan Crabtree P.S. The USA is the world's #1 performing non-metric country. Base 10 measurement makes math too easy! The USA used French origin math books in the19th century yet kept the British imperial system of weights and measures. Whoops!