German grade conversion formula

Today, I got my first result from a German exam. If you didn't know, the German grading system is a bit different from the Romanian one: the grades are from 1 to 5, where 1 is the maximum grade and 4 is the last passing grade (5=failed). So, if you get 1 at your exam in Germany, you don't have to cut your veins, or jump from a building - but rather go out and buy your friends some beer, because you're da' man.
Also, you can have grades with fractions, like 1.3, 1.5, and so on.

Today I got a result that didn't tell me too much, because where I come from, the grading system goes from 1 to 10 (where 10 is the maximum grade). So, I came up with a formula to convert from German grades to Romanian grades:

RomanianGrade = 5/3 * (7 - GermanGrade)

If you want to have fun converting your grades from Romanian to German grading system, use the following formula:

GermanGrade = 7 - 3/5 * RomanianGrade