
I find that when I am teaching math within my classes (especially word problems) a lot of my students "shut-down" because of their previous experiences with math and word problems. So, it isn't always about their base knowledge they have coming into the classrooom, it is their self-worth from other instructors and classes too.
Roger
Math is a kind of dicotomy to subjects which appeal to students who are allowed to be "creative," in that, they may for example, be assigned an essay on the history of something, and in that essay they are allowed to give their feelings and opinions on a number of things, all of which will be taken into consideration toward their grade on that subject. In math word problems, there is only one objective correct answer, which is usually a number. The answer is one thing, and if it isn' that one thing, it is incorrect. This is where the problem arrises. No amount of commentary will change the fact that in math word problems, there is only one answer.
The nervousness comes because of the knowledge that they must actually read, understand, and responde directly to the problem, or it is incorrect. There is only one correct answer, and this can cause anxiety in a group of students who've been taught that truth in all things is relative, even in math.