Abstract:
The objectives of this research were to develop and evaluate academic values of a supplementary book on irrational numbers for students in lower secondary schools. The sample group included 70 mathematics teachers and 5 experts from Mathematics Program and Mathematics Education. The research instruments were a supplementary book on irrational numbers for students in lower secondary school, an academic accuracy checklist for supplementary reading books by experts from Mathematics Program and Mathematics Education with reliability of 0.75, a questionnaire for the first and second group discussion, and an evaluation form for academic values with reliability of 0.78. Data were collected from the group discussions and academic value analysis. The data were analyzed by using percentage, mean, standard deviation, and t-test.
The research results showed that the supplementary book developed was consisted of information about the history of irrational numbers and calculation criteria for irrational numbers using the numerical method, which was developed and validated using the mathematical accuracy by the experts and improved in accordance with the analysis of the first and second group discussions held with the experienced (or above) mathematics teachers showed that the academic values evaluated by the experts, the teachers attended the group discussions, and the teachers who did not attend the group discussions, were at a high level (4.36), a very high level (4.73), and a high level (4.47), respectively. In addition, the academic evaluation between those two group discussions was statistically different at a significance level of 0.05.