The aim of this research is to characterise how pre-service primary teachers notice students' reasoning related to the fraction concept sub-constructs: part-whole, measure, quotient, ratio, operator and reasoning up and down. 82 pre-service teachers analysed primary school students' answers to five fraction problems. Each student's answer shows different characteristics of students' reasoning in each sub-construct of the fraction concept. Five profiles of pre-service primary teachers have been identified according to how they used the mathematical elements to recognise students' reasoning.