Students enrolled in post-secondary developmental mathematics courses hold mathematical misunderstandings that begin before their college careers. Specifically, these students struggle with conceptual understanding of fractions, ratios, and proportions. The Common Core State Standards in Mathematics outline standards for K-12 mathematics education. Standards for fractions, ratios, and proportions are found in grades 3-7. Through a research instrument, collegiate developmental mathematics students were investigated regarding their understanding of these standards. It was determined that participants showed evidence of limited knowledge of the examined areas involving fractions, ratios, and proportions. Because it seems that this lack of understanding is rooted early in their educational careers and is continued throughout students' academic careers, it is hoped that this work can be a starting point for future work in this field that may apply to investigating ways to bridge these gaps in mathematical understanding.