Development of Teaching Materials by Implementing Problem Based Learning-Oriented Virtual Manipulatives to Improve Thinking Ability Critical And Mathematics Problem Solving Class VIII Students of Mars Private Junior High School

This study aims to describe: 1) the validity, practicality and effectiveness of teaching materials developed by implementing virtual manipulatives and problem-based learning oriented; 2) improvement of critical thinking and problem solving skills of SMP MARS Pematang Siantar Class VIII students by using teaching materials developed by implementing virtual manipulative and problem based learning oriented. This research is a development research. The development model used in this study is the Thiagarajan model. The results showed that: 1) the teaching materials developed by implementing virtual manipulative and problem-based learning oriented were declared valid, practical and effective; 2) there is an increase in critical thinking and problem solving skills for students of SMP MARS Pematang Siantar Class VIII by using teaching materials developed by implementing virtual manipulative and problem-oriented base learning. In the first trial there was an increase in the value of critical thinking skills of 0.35 and the value of problem solving abilities of 0.44 with moderate criteria. Likewise, in the second trial there was an increase in the value of critical thinking skills of 0.42 and the value of problem-solving abilities of 0.53 with moderate criteria.