This paper discusses the learning of concepts in undergraduate Linear algebra by pre-service teachers in mathematics. The focus is set on the bi-linear and multi-linear forms on a real vector space, exemplified by the dot product of vectors and determinants, respectively. Moreover, the paper identifies and describes discrepancies between students' achievements regarding the development of procedural and conceptual understanding. They are investigated through two types of exercises, discussing questions and multiple-solution tasks (MSTs), whose solutions differ under three criteria.