This research aims to analyze the ability of mathematical communication problem solving who had reflective cognitive style’s, and impulsive cognitive style are in the first grade of SMP Negeri 1 Sumberrejo on mathematical written, drawing mathematically, and mathematical expression aspects. The research is a qualitative research with subjects in this research were eight students of class VII C SMP Negeri 1 Sumberrejo which consisting of four students with reflective cognitive style’s, four students with impulsive cognitive style’s. The subject in this research was taken by using purposive sampling technique. Data was collected by the results of written tests and interviews. Data analysis techniques used data reduction, data presentation, and conclusion. The validity of the data uses time triangulation that compared data of the first task and interview with the second task and interview. The results showed that: (1) students with reflective cognitive styles: the mathematical written ability are on the fourth level, drawing mathematically are on the third level, and mathematical expression is on the third level, (2) students with impulsive cognitive styles: the mathematical written ability are on the third level, drawing mathematically are on the second level, and mathematical expression are on the second level.

The purpose of this research are to know whether the average problem-solving abilities mathematics of students who were taught using Think Talk write learning model can achieve exhaustiveness learning and whether the average problem solving abilities mathematics of students who were taught using Think Talk write learning model are better than average the average problem-solving ability of students who were taught using the learning model of conventional. The population in this research is VII grade students of SMP N 1 Klambu. By random sampling technique obtained two classes as a research sample, namely class VIIC as the experimental class and class VII B as the control class. The data was collected by the documentation methods, test methods and observation methods. Based on the analysis of research results is known that 83,3% of students who were taught using Think Talk write learning model can achieve exhaustiveness learning. In addition, there are significant differences between the average problem-solving abilities mathematics of students who were taught using the learning model of Think Talk write with students who are taught using the learning model of conventional. From the above description, it can be concluded that the application of Think Talk write learning model is effective towards problem-solving ability mathematics of VII grade students of SMP N 1 Klambu at the material quadrilateral.

This paper discusses the development of collaborative learning models in modification by means of active learning, in this development to follow up P1, wherein P1 there are still many weaknesses weakness after identification on its application, it is hoped that this P2 can cover all the weakness and can cover the deficiencies in every development, hope development that will be done so as to create a new model of learning and can be applied to learners on mathematics. Learning activities of learners are seen before and after the development of active collaborative learning model (KA). By increasing the learning activities of PKBM environmental learners in Cengkok Village, Ngronggot District Nganjuk Sub-Province, it can be useful to motivate and increase learning activities so that the learning achievement of Mathematics is conducive for students who are trying to get C package.

This paper is described the properties rank of square matrices over commutative ring if connected with its determinant. Rank of n x n matrix over a commutative ring is less than n if it’s determinant is an element of zero divisors in R. Rank of n x n matrix over a commutative ring is n if it’s determinant is not an element of zero divisors in R.

Swine flu is an acute respiratory infection that attacks the bodys organs especially the lungs. The disease is caused by Influenza Virus Type A, type H1N1. In this article constructed mathematical model of the spread of H1N1 disease. Mathematical model that created the model Susceptible, Exposed, Infective, and Treatment. The existence of behavior change and influence of infected individual density become the reason of model formation with saturation occurrence rate. From the dynamic analysis, the model has two equilibrium points, that is, a stable equilibrium free equilibrium point when the basic reproduction number is less or equal to one, and an endemic equilibrium point that exists and is stable when the basic reproduction number is greater than one. Finally, the results of the analysis prove the control of the spread of disease into a disease-free state.

Lesson study (LS) is a continuous assessment activity conducted by a group of teachers / lecturers on a regular and continuous basis to test and improve the effectiveness of learning. Lesson study through planning activities, implementation (do) and reflection (see) collaboratively which aims to improve the quality of learning. Lesson Study conducted can encourage students to learn actively, creatively, precisely and fun. Lesson Study can also improve the observation capabilities in the classroom so that teachers can pay attention to the students one by one. Lesson study activities conducted at SMPN 1 Baureno aims to improve teacher competence and improve the quality of learning in the classroom. At the time of open class, learning is done by approach of PBL (Problem Based Learning) which is equipped with worksheet. The PBL (Problem Based Learning) approach or problem based learning is chosen because it can improve students retention by finding principles and formulas. According to the observer, open class activities with group discussion methods can improve students understanding and retention of the material so that students remember longer material and can apply the formula appropriately. With Lesson Study more enjoyable learning so that students are more enthusiastic in following learning.

Multiplication is one of the important materials taught in elementary school because it is very often found its application in everyday life. In addition, mathematical topics for higher levels still use multiplication operations. In essence the plot is a recurrent sum, but not necessarily the multiplication concept is taught in a way that depends only on repeated summations. Students need to be trained to shift from thinking adding (additive thinking) to multiplicative thinking. Multiplicative Thinking is a prerequisite for being able to solve problems involving fractions, decimal numbers, percent numbers, and comparisons. The purpose of writing this article is to identify and describe the way of thinking elementary school students, especially students in grade 3 and 4 in solving multiplication counting problems. The classification of students into the form of multiplicative or additive ways of thinking seen from the work of students then grouped based on its characteristics.