My advisor is responsible for assigning teachers to conducting excercises to lectures. Since there is a lot of students (and groups) sometimes last year students help by taking excercises in some groups. For the past 5 months I've been employed by the university and I've worked a couple of hours a week taking classes, without a formal position at the university (and for sure won't have until I finish my masters).
Right now I am writing a CV and I would like to include the last 5 months in my work experience but I don't know how to name my position - is "Math teacher @ university" a good one?