The background of this study is the lack of mathematical communication skills (MCS) of junior high school students in Cimahi. This study aims to examine the achievement and improvement of MCS of junior high school students in Cimahi by realistic mathematical approaches. This study involved two groups, namely the experimental group and the control group. All groups were given a pretest and posttest. The experimental group obtained mathematics learning with realistic mathematical approaches as treatment and control groups obtained mathematics learning as usual as a treatment. This research method is an experimental research with pretest-posttest control group design, namely the design of the pretest posttest control group that involves two groups and randomly sampled classes. The population in this study were junior high school students in Cimahi, while the sample consisted of two randomly selected classes. Obtained class VIII M (experimental class) and class VIII K control class. The instrument used was a 5-item MCS description test, then the skills scores MCS students' were analyzed with descriptive and inferential statistics using assistance Minitab 17. Based on the results of the study, it was concluded that the achievement and improvement of students' MCS using mathematical realistic approaches were better than students who used ordinary learning.

The research was caused by the poor of mathematical problem solving ability of students. This research aimed to compare of mathematical problem solving between students who learned through problem based learning and scientific approach. The method was an experimental method with a pretest-posttest control group design involving two groups and random sampling. At the first and end of learning, the two classes are given a test. The population in this research were Madrasah Aliyah students in Cimahi, while the sample consisted of two randomly selected classes. One class  which was given problem based learning and other class was given a scientific approach. The instrument was a set of  5-item mathematical problem solving test description, then those were analyzed with descriptive and inferential statistics using the help of minitab 17 software. Based on the results of the research, the conclusion was  the improvement of  mathematical problem solving  of students using problem based learning was better than students who use a scientific approach.

Basically education is considered as an important tool to build the intelligence and personality of the Indonesian nation. The purpose of this study was to determine the effect of the simulation method and the demonstration method on student learning outcomes at STKIP PGRI Sukabumi. This type of research is associative research with a quantitative approach. The population in this study were all STKIP PGRI Sukabumi students. The sample technique used in this research is random sampling technique. With a sample of 100 students. The results of the study showed that there was a positive and significant influence between the variables of the simulation method and the demonstration method on student learning outcomes with a value of (25.267) > (3.09). While the sig column. shows a probability value of 0.000 < 0.005. The magnitude of the contribution of the effect of the simulation method and the demonstration method on learning outcomes is 34.3% and the remaining 65.7% is influenced by other factors.