This study aimed to 1) create students' worksheet (LKPD) for mathematics
learning based on Open-Ended Problems on students' mathematical creative
thinking skills that meet the validity aspect. 2) create students' worksheet
(LKPD) for mathematics learning based on Open-Ended Problems on students'
mathematical creative thinking skills that meet practical aspect. 3) create
students' worksheet (LKPD) for mathematics learning based on Open-Ended
Problems on students' mathematical creative thinking skills that meet the aspect
of effectiveness. This research used 4D development which has been modified
into three stages, namely Define, Design, and Develop. The trial was carried out
in MTs. Wathoniyah Islamiyah Kebarongan with research subjects of 9 students
in Grade IXA. From the research, it was found that the mathematics learning
worksheets that had been developed met the validity aspects as measured by the
assessment of the validation results of experts with an average score of 4.1. The
practicality of the LKPD was measured based on the observation of the
implementation of the LKPD which was shown to be fulfilled in the fully
implemented category. The teacher's response indicated an average score of 4.0
meaning that the mathematics worksheets are practical to be used in learning
activities. The effectiveness of the LKPD was shown by the fulfillment of the
established effectiveness indicators, namely the average N-Gain normality test,
the results of which were carried out through the results of the pretest and
posttest. The N-Gain normality test got an average score of 0.5130 which was
interpreted as moderate. Thus, the development of mathematics worksheets is
effective on students' creative thinking abilities. It can be concluded that the
LKPD developed is valid, practical, and effective