This study explored whether and how prospective teachers (PTs) fraction sense could improve in the setting of a Number and Operations course. the results from the interviews with seven participants provide evidence that their performance and flexibility in comparing fractions improved. The authors found that 6 of the 7 interview participants adopted at least two new valid strategies for comparing fractions. Consequently, these findings can guide mathematics teacher educators how to support PTs to reason meaningfully and flexibly about fraction magnitude.