In order to solve our particular problem of finding all possible abelian groups of order p2, p prime, or even the larger problem of finding all possible abelian groups of given order n, we need to consider the structure of finite abelian groups only. However, it turns out to be not much more difficult to find the structure of a wider class of abelian groups, namely those which are generated by a finite subset of their elements. We call these finitely generated abelian groups.