Project-based learning (PjBL) is an appropriate learning model that can shape students’ scientific, social and higher-order thinking. Implementing PjBL in education gives students the freedom to plan their own learning activities, conduct projects collaboratively and produce products. In a healthy menu project, PjBL can help students calculate their excess weight. The purpose of this study was thus to design a healthy menu that assists Indonesian junior high school students solve numeracy problems using obesity context. The method followed a design research type validation studies using observation and document reviews as data collection techniques. This study produced a learning trajectory that can help grade VII students solve arithmetic operations using obesity context through two activities. In the first, the students were asked to record their respective heights and weights, then use them to determine their body mass index (BMI) and body mass ratio (BMR). Then, the students confirmed their necessary daily caloric intake, and categorized their BMI and BMR results as underweight, normal, overweight or obese. In the second activity, the students developed healthy menus per their respective tastes based on their weight categories from the first activity. The study concluded with the students successfully producing healthy menus that they designed according to their calculated required daily caloric intake.

The Traveling Salesman Problem (TSP) is very well known as one of the optimization problems of circuit of Hamiltonian , which will seek for the shortest route that must be passed by a number of city salesmen exactly once and will return to the initial city. Genetic Algorithm (GA) and Simulated Annealing (SA) are one method that can be used in TSP case. Fertilizer distribution at PT. Sahabat Mewah dan Makmur (SMM) in Belitung which is one of the branches of PT. Austindo Nusantara Jaya Group does not yet have an optimal fertilizer distribution schedule, where when fertilizer will be distributed from the starting point of distribution to the location of storage warehouses, it is not determined which location points will receive delivery, shipments are made to warehouse locations that still have enough storage space or stacked in the nearest warehouse. PT.SMM distributes fertilizer from Port of Tanjung Pandan to warehouses in Jangkang, Balok, Ladang Jaya, Sari Bunga, and Aik Ruak. The results show that in the GA of 120 routes, there are 8 routes with a distance of 175 km; In SA, the shortest distance is equal to GA, which is 175 km.

This study aims to determine the role of activities in learning the central tendency materials (mean, median, and mode), which is expected to be able for helping students understanding the concept of statistical learning in grade VIII. The method used in this study is Validation Studies type Design Research involving students of MTs Negeri 1 Palembang. There are three stages in the design research type of validation studies, namely Preparing for the experiment; The design experiment in the form of a Preliminary Teaching Experiment (Pilot Experiment) and Teaching Experiment; and Retrospective analysis. In this study only that of preliminary teaching experiment is considered. The activity begins with questions about remind the presentation of data in the diagrams, then understanding the concept of the mean, the median, and mode, the question of associating the mean and median to determine the mode. The results of the learning experiment show that through the given questions can support students to understand the concept of the central tendency and know the relevance. Errors in doing activities because students are not careful in reading information on the questions, weak in the ability to count, and don’t remember or not understand about the materials given.

The demands of the 21st century require students to be reliable communicators, creators, critical thinkers, and collaborators in solving problems through student involvement in learning. This research aims to explore the student’s mathematical reasoning abilities and problem-solving skills in mathematics using the cost of payments for water use as context. The subject of this research was eight-grade students of SMPN 19 Palembang. This research uses the method of design research with validation studies type which three stages, namely Preparing for the experiment; The design experiment consists of two cycles (Pilot Experiment and Teaching Experiment); and Retrospective analysis. The study results show that learning using receipts of water payments as a medium for saving water can help students develop reasoning and problem-solving skills in mathematics learning. However, students not accustomed to using information obtained from the analysis to solve the given problem. Students tend to provide non-mathematical arguments on each issue that require students to provide discussions about the learning material, especially data presentation.