​This study aimed to investigate the knowledge content of pre-service teachers regarding fractions. To achieve the study's objectives, a test consisting of three questions was administered to 127 students majoring in education at the University of Jordan. The results indicated that the pre-service teachers lacked adequate knowledge of fractions. Various types of errors were observed in identifying fractions on the number line, such as: lack of understanding of fraction values, difficulty in dividing the whole into parts, and treating the numerator and denominator as separate numbers. Additionally, weaknesses in geometric skills were identified, including how to partition the number line, reversing the direction of partitioning, interpreting the fraction’s position as a rounded decimal point, treating it as an ordered pair, or considering it as a column in a histogram. Some students also based their fractions on how they read them. The prevalence of common error types ranged between 1% and 26%. Based on these findings, the study recommended conducting diagnostic assessments in mathematical concepts and further research in this area.​