The rational number notion is being gradually implemented ever since the sixth year of primary school study. Implementing of this notion is progressing gradually form the work with its representatives (as decimal number and fraction) to the definition of rational number notion.We were interested in reception of this notion by the graduates of different secondary schools. This article deals with the analysis and summarisation of results obtained from a first year university students, who were solving particular tasks in the work material prepared by authors of this paper. Particular tasks were arranged for progressive testing of student’s ability to work with a rational number at different levels up to ability to correctly define the representatives of such number field. We have focused mainly to investigation, which of the rational number representatives is more preferred by the respondents.