Proportional reasoning is one of the basic building blocks of mathematics. It is a critical skill for students to cope with many problems they encounter in mathematics and daily life. Developing proportional reasoning skills is one of the most important goals of the middle school mathematics curriculum. This study aims to reveal proportional reasoning and to present the place and importance of this concept in middle school mathematics by reviewing relevant sources. This study is a review study presented by gathering and reporting relevant documents designed within the scope of qualitative research. Resources related to the concept of proportional reasoning in the literature were collected and presented with the document analysis technique. Proportional reasoning is a comprehensive mathematical thinking process that does not consist of simply memorizing the concepts of ratio and proportion but rather requires a deep understanding of the relationships between quantities. Three different question types were used to measure this skill: missing value, numerical comparison, and qualitative reasoning questions. There are formal strategies where algebraic rules are applied to solve proportionality questions and informal strategies where proportional relationships are used.

Proportional reasoning, ratio, proportion.