Analysis of elementary school mathematics textbooks on teaching of the concept of ratio and rate: Focusing on the 2015 revised elementary school mathematics textbooks

Objectives The purpose of this study is to analyze how prior knowledge is utilized in introducing the concept of ratio and how context is utilized in introducing the concept of rate in 11 elementary school mathematics textbooks according to the revised 2015 curriculum, and to derive implications for teaching ratio and rate based on this. Methods From prior research, we derived the prior knowledge(subtraction comparison, division comparison, orrespondence relationship, multiple-batches perspective) that can be utilized in the introduction of the concept of ratio and the form of context utilization(whole-part rate, part-part rate, rate of two equal quantities) in the introduction of the concept of rate, and based on this, we analyzed the ratio and rate sections of 11 textbooks. Results In the introduction of the concept of ratio, 7 out of 11 textbooks were classified into passive use of subtraction comparison-division comparison, 2 textbooks were classified into active use of subtraction comparison-division comparison, 1 textbook was classified into subtraction comparison-division comparison and utilization of correspondence relationship, and 1 textbook was classified into utilization of multiple-batches perspective and correspondence relationship. In the introduction of the concept of rate, 8 out of 11 textbooks utilized the whole-part rate, 2 textbooks utilized the part-part rate, and 1 textbook utilized the context of the rate of two equal quantities. Conclusions This study confirmed that the 2015 revised elementary school mathematics textbooks attempted various approaches in introducing the concepts of ratio and rate, and the results of this analysis provide implications that can contribute to increasing the effectiveness of learning ratio and rate in elementary school mathematics education.