The US's falling position in mathematical proficiency is caused by "dysfunctional beliefs". The examples of "dysfunctional beliefs" given are:
“The goal of mathematical activity is to provide the correct answer to given problems, which always are well defined and have predetermined, exact solutions."
“The nature of mathematical knowledge is that everything (facts, concepts, and procedures) is either right or wrong with no allowance for a gray area.”
Now, while I do believe that students of advanced mathematics should be given partial credit for problems that were solved in the correct manner with a slight addition or subtraction error, this isn't what they are talking about. The author is speaking of elementary mathematics. In other words, 2x2 is no longer equal to 4.
I wonder how the author would feel about walking into a building engineered with "grey area" mathematics.