If you did a degree which is low on math (read economics, psychology), but want to proceed to a more mathematically loaded master, how would you document your knowledge?
Are there standarized examinations that are widely recognized?
That would also be a way of discovering how weak one is in math, not only to prove towards others.
If you are applying for math graduate school in the US many schools would require the Math subject GRE. See http://www.ets.org/gre/subject/about/content/mathematics for what is covered. It's a multiple choice test but it's pretty challenging (and requires you to work fast).