R. James Milgram 15MB e-book pdf:

It has long been felt that the mathematical preparation of pre-service teachers throughout the country has been far too variable, and often too skimpy to support the kind of outcomes that the United States currently needs. Too few of our K – 12 graduates are able to work in technical areas or obtain college degrees in technical sub jects. This impacts society in many and increasingly harmful ways, and it is our failure in K – 8 mathematics instruction that is at the heart of the problem.
This is especially true when we compare outcomes in the United States with outcomes in countries that do a better job of teaching mathematics, countries such as Poland, Hungary, Bulgaria, Romania, Singapore, China, and Japan, to name a few.
It has also been increasingly recognized that if we are to improve our performance in K – 8 mathematics instruction, pre-service teachers should take focused, carefully designed courses directly from the mathematics departments, and not, as is often the case, just a single math methods course taught in the Education School. A focused two year sequence in the basic mathematics teachers have to know is the minimal mathematics sequence that pre-service teachers need in order to to successfully teach students in K – 8.