Mathematical creative ability is one of the most important skills students must have to process the information provided in resolving the problem. Before using mathematical creative skills, prior knowledge becomes the most crucial thing that allows students to connect all existing information so that they can construct new knowledge through assimilation or accommodation processes. The process of forming mathematical concepts with metacognitive questions that might be carried out by students causes a metacognitive process in students that will affect their mathematical behavior. The purpose of this study is to (1) analyze prior knowledge of what students miss or forget so that they have difficulty to answer the given geometry problem, (2) how the learning path of creative thinking of students with the application of metacognitive approach. This type of research is Design Research to improve the quality of learning. This type of research is research design, data collection techniques .The researcher gave 2 geometry questions to 38 8th graders selected randomly in SMP Medan city. Questions given are tailored to Cognitive level 4 (C4) for questions 1 and C5 for question 2 based on Bloom's taxonomy. Data analysis techniques are descriptive qualitative.This study shows that prior knowledge becomes important to build students' mathematical creative ability to gain new knowledge, especially in the field of geometry. The most problematic topics that make it difficult for them to understand geometry are the area of the rectangle and the cube webs. In dividing the rectangle into two equal parts, students still have not created another form of flat build or have not been able to get out of the rectangular pattern or exactly the same as the available problem. There are five phases of learning trajectory of hierarchically creative mathematical thinking, which is orientation to problem, problem solving plan, plan realization, previous knowledge mastery / concept of mathematical creativity and evaluation of result obtained. Students do metacognition on the learning path of creative thinking in a comprehensive way from evaluation to planning, action to the formation of prior knowledge and selection of creative ideas. From these explanations, it is important that teachers need to ensure students have enough prior knowledge to make it easier to construct new knowledge, as well as to make learning fun and meaningful so that students will remember knowledge in long-term memory.

This study aims to determine the effect of the Problem Based Learning model on students' mathematical problem solving abilities. In addition, this study also looked at the interaction between learning and gender on students' mathematical problem solving abilities. This research was a quasi-experimental study. The population in this study consisted of all students in junior high school (SMP) 7 Padangsidimpuan totaling 423 students. The study sample consisted of 46 students, namely 23 students in grade VIII-3 and 23 students in grade VIII-6. Data analysis was performed with two-way ANOVA using SPSS version 21.0. The results of this study indicate that there is the effect of the Problem-Based Learning model on mathematical problem solving ability of students. In addition the result also show that there is no interaction between learning and gender on students' mathematical problem solving abilities.

This research aims to describe: (1) product validity of learning device development based on Van Hiele model, (2) the practicality of product development of learning device based on Van Hiele model, (3) the effectiveness of product development of learning device based on Van Hiele model, (4) improvement of students' spatial skills by using the tools that have been developed based on Van Hiele model, (5) increase the ability of selfconcept students by using the device that has been developed based on Van Hiele model. The research was a development research. The development model was used 4-D model consisting of four stages, namely: Defining, designing, developing and distributing. The study to test trials was conducted on the class VIII of MTsS Ulumuddin. Test trials 1 conducted on the class VIII-2 and test trials 2 was conducted on the class VIII-3. Based on the results of the development it's showed that: (1) The valid learning tools developed with the total average validity of RPP's score was 4.50, Student Book's score was 4.30, Master Book's score was 4.30, and LAS's score was 4.40; (2) The practical learning tools developed showed based on students' activities within the prescribed tolerance limits; (3) The effective learning tools developed can be seen based on from the students' learning completeness in the classic, and achievement of learning objectives of at least 80% (4) The average achievement of students' spatial ability in the trial I was 3.15 increased to 3.51 in trial II; and (5) The average achievement of students' self-concept trial I was 3.03 increased to 3.16 on trial II.

ABSTRAK Penelitian ini bertujuan untuk mengetahui apakah kemampuan komunikasi matematis siswa yang diajar dengan model pembelajaran kooperatif tipe Think Talk Write (TTW) lebih tinggi daripada kemampuan komunikasi matematis siswa yang diajar dengan model pembelajaran kooperatif tipe Think Pair Share (TPS) pada pokok bahasan kubus dan balok di kelas VIII. Jenis penelitian ini adalah eksperimen. Populasi dalam penelitian ini adalah seluruh siswa kelas VIII SMP N 27 Medan semester genap, yang terdiri dari 9 kelas. Sampel dalam penelitian ini adalah dua kelas yang dipilih secara acak dimana kelas VIII-2 sebagai kelas eksperimen TTW dan kelas VIII-3 sebagai kelas eksperimen TPS dengan masing-masing jumlah sampel 40 orang dalam tiap kelas. Penelitian ini menggunakan satu jenis instrumen yaitu post-test dalam bentuk essay. Dari hasil penelitian yang diberikan, diperoleh  nilai rata-rata post-test kelas eksperimen TTW sebesar 70,3125 dan kelas eksperimen TPS memperoleh nilai rata-rata 64,6875. Berdasarkan pengujian hipotesis yaitu dengan mengggunakan uji t dengan  diperoleh thitung< ttabel (1,5857 < 1,667). Hal ini menunjukkan bahwa H0 diterima dan ditolak sehingga dapat dinyatakan kemampuan komunikasi matematis siswa yang diajar dengan menggunakan model pembelajaran kooperatif tipe TTW lebih tinggi daripada kemampuan komunikasi matematis siswa yang diajar dengan menggunakan model pembelajaran kooperatif tipe TPS.Kata kunci: Komunikasi matematis, TPS, TTW ABSTRACT This research aims to know determine whether the mathematical communication ability of  students who learn with Think Talk Write (TTW) cooperative learning model is higher than mathematical communication ability of  students who learn with Think Pair Share (TPS) cooperative learning model on the material of the cube and the beam grade VIII. Type of this research s using quasi experiment. Population in this research is all student grade VIII SMP N 27 Medan., consists of 9 classes. The sampling in this research was done by random sampling, VIII-2 is called experimental class TTW and VIII-3 is called experiment class TPS which amounts to 40 students per class. The instrument used in this research is post-test only design. From the research conducted, obtained the average value of post-test experimental class TTW amounts 70,3125 and the average value of post-test experimental class TPS amounts 64,6875. Based on hypothesis testing by using t test with  obtained thitung< t tabel (1,5857 < 1,667). This shows that Hoaccepted and Ha rejected so that it can be stated that the mathematical communication ability of  students who learn with Think Talk Write (TTW) cooperative learning model is higher than mathematical communication ability of  students who learn with Think Pair Share (TPS) cooperative learning modelKeywords : Mathematical communication TPS, TTW

The purpose of this study was to determine whether there was an effect of CTL learning and conventional learning with early mathematics abilities on the understanding of the fourth grade students of SD Negeri 117471 Sibargot. The research method used was an experiment using pre-test and post-test control group design. Hypothesis testing in this study used a two-way analysis of variance (ANOVA) test with a significance level of α = 0.05. The results of this study indicate that the sig. for CTL (MP₁) and Conventional Learning (MP₂) is the result of tcount -2.911> ttable 2.002, so it can be concluded that H1 is accepted, which means that there is a significant influence of the learning model on understanding mathematical concepts; sig value. for Mathematical Initial Ability (KAM) with the result of tcount -6.434> ttable 2.002 shows that the mean of the first group, namely high initial ability (KAMt) is higher than the second group, namely low initial ability (KAMr), so it can be concluded that H2 is accepted, which means that there is an influence. significant initial ability to understand mathematical concepts; sig value. for the effect of the Learning Method and KAM simultaneously on understanding mathematical concepts with the results of the value of Fcount 24.933> Ftable 3.16. So it can be concluded that H3 is accepted, which means that there is an effect of learning methods and Early Ability simultaneously on understanding mathematical concepts.