The purpose of this research are: (1) to know mathematical critical thinking ability of students who follow learning with model of Problem Based Learning (PBL) is higher than students who follow conventional learning, (2) to know student response to model of Problem Based Learning (PBL) during learning takes place. This study included a quasi-experimental type of study. The result of the research shows that students' mathematical critical thinking ability which follows learning model with Problem Based Learning (PBL) is higher than students who follow conventional learning. Based on hypothesis test obtained tcount = 2.59 and ttable = 1.672 with dk = 58 and significance level so that it looks that tcount = 2.59 > ttable =1.672. The result of student's questionnaire analysis shows that student's response is positive to Problem Based Learning model, which means that students are motivated in learning by using Problem Based Learning model. So, it can be concluded that the model of Problem Based Learning effect on students' critical thinking skills mathematically.

The purpose of this study was to determine the effectiveness of Lectora Inspire assisted mathematics learning media on the number sense ability of elementary school fifth grade students. This research is a development research using 4-D design that is Define, Design, Develop and Disseminate or adapted to 4-D model that is defining, designing, developing and distributing. The test sample was the fifth grade students of Medan Kartika I-2 Private Elementary School. Products developed after being declared valid by experts / experts, then tested. Product validation results are stated to be very valid. Based on the results of the validation of learning materials by 93.82%, instructional design by 91.03%, media experts on Lectora Inspire by 87.5%, student responses to Lectora Inspire amounted to 95.57% and the teacher's response to the Lectora Inspire amounted to 89.56 % in very good category. Based on the average value of the data gain the ability of the student's number sense is 0.70 in the high category. Increased ability of student number sense is 0.27. From the results of the analysis, it can be stated that by using Lectora Inspire assisted mathematics learning media in learning related to fractional materials can increase the number sense ability of students.

The objectives of this study were (1) to describe the use of mathematics learning media assisted by the Lectora Inspire software to improve the number sense ability of students, (2) to describe the increase in the ability of students' number sense through mathematics learning media assisted by Lectora Inspire software. The ability of the number sense studied is related to ordinary fractional material. Indicator of the number sense ability in question is understanding the basic meaning of fractions, understanding the effect of operations on fractions and using appropriate calculations. This study is a classroom action research, carried out at SD Swasta Kartika I-2 Medan in the academic year 2018/2019. Based on the results of the study showed that the mathematics learning media assisted by the Lectora Inspire software in the developed class V SD fraction material was declared feasible to use because it could affect the students' number sense ability. Based on the results of the final test in cycle I, there were 15 students (41.67%) achieving KKM scores, while the final test results in cycle II obtained 31 students (86.11%) achieved the KKM score. Based on the results of the end of cycle I and II tests obtained as many as 16 students (44.44%) experienced an increase in the number sense ability related to fraction material. The results of the observation sheet for teacher and student activities in the first and second cycles are in good category. Thus it can be stated that there is an increase in the number sense ability of students through mathematics learning media assisted by the Lectora Inspire software.

The purpose of this study is to describe the preparation, implementation and assessment related to the implementation of the Batak Angkola culture-based Multiple Intelligences approach in the thematic learning of grade IV SD 100620 Pargarutan Julu, South Tapanuli District. This research uses a qualitative research approach with descriptive research type. The subjects of this study were grade IV teachers and grade IV students. Data collection techniques used were observation, interviews, and documentation. Data analysis techniques consist of data reduction, data display and conclusion drawing. The results showed that the implementation of the Multiple Intelligences approach in thematic learning in grade IV SD 100620 Pargarutan Julu, South Tapanuli Districttook place well. The teacher has used varied learning methods and strategies for the Batak Angkola culture, including using lecture and story methods for students who are superior in verbal-linguistic intelligence, demonstrations in ritual ablution for students who are superior in physical-kinesthetic intelligence. For students who excel in multiple intelligence, the teacher teaches with presentations that combine creative linguistic, mathematical and kinesthetic methods with creativity. The learning assessment is reviewed from 3 aspects namely; 1) cognitive by oral, written and assignment tests, 2) affective by observation and self-assessment, and 3) psychomotor with project and practice assignments. It can be concluded that the teacher has carried out activities to provide apperception and motivation and to carry out multiple intelligence-based activities to develop the nine types of intelligence, including: linguistic-verbal, mathematical-logical, visual spatial, kinesthetic, musical, interpersonal, intrapersonal, naturalist and existentialist. So with the implementation of the Multiple Intelligences approach, thematic learning is more fun and meaningful.

The purpose of this study is to describe the cultivation of numerical literacy with HOTS questions in mathematics learning. This research is a qualitative research conducted with the following stages: (1) identifying the problems that arise in the cultivation of numerical literacy, (2) determining the focus of the problems that arise in the cultivation of numerical literacy, (3) determining the subjects in the research, (4) collecting the required data, (5) analyze the research data, and (6) draw conclusions. The subjects in this study were teachers and 27 students of 4th grader in SDS PKMI Ephesus Aek Batu. Methods of data collection by interview, observation and documentation. The data analysis technique was carried out by qualitative analysis using an interactive flow model. The results of the research obtained are the cultivation of numerical literacy with HOTS questions in mathematics learning carried out in online learning activities, offline and home visits.