Developing LKS Using a Realistic Approach to Improve Students’ Mathematical Problem-Solving Abilities

This study aims to produce LKS with a realistic approach to improve the problem-solving abilities of high school students in grade XI of linear programming material that meet the criteria of valid, practical, and effective. This study uses the ADDIE model, which goes through five stages: analysis, design, development, implementation, and evaluation. The subjects of this study consisted of 32 students in grade XI IPA 1 of SMA Negeri 6 Medan. The results of the study show: (1) The results of the LKS validation assessment based on material experts and media experts are both 85.07% included in the "very valid" category. The results of the validation assessment based on the teacher response questionnaire are 86.81% included in the "very valid" category, and based on the student response questionnaire, 87.5% are included in the "very valid" category. (2) The results of the practicality data analysis are the readability of the LKS that have been developed, with the average results showing that ≥70% are included in the "practical" category, but there are suggestions and input from students. The results of the practicality analysis based on the teacher's response questionnaire obtained a percentage of 85% included in the "very practical" category, and based on the average response questionnaire of class XI IPA 1 students, 88% were included in the "very practical" category; (3) The results of the effectiveness data analysis are the results of the student's post-test percentage of 87.5%, which means it is effective so that problem-solving abilities increase, and the N-Gain value of 0.63, or the "medium" category, is said to be effective.