This community service activity aims to provide assistance to SMK teachers in Mataram City in developing project-based learning to design, implement, and evaluate project-based mathematics learning. The specific target to be produced from this service activity is the optimal understanding of SMK teachers throughout the city of Mataram related to the planning, implementation, and evaluation of project-based mathematics learning. To achieve this target, mentoring was carried out for SMK teachers in Mataram City, each represented by 2 teachers in each partner school. Mentoring activities are carried out with a series of activities, namely (1) Seminars related to the general description of project-based learning and dissemination of research results that are still related to the need for project-based learning to be implemented in schools, (2) Workshop on project-based learning design, (3) Workshop on implementation project-based learning, (4) project-based learning evaluation workshops, (5) forum group discussion results from the implementation of activities in each school. The results of the service activities showed a positive response from the training participants and an increase in participants' understanding of project-based learning in mathematics learning.

Problem-based learning (PBL) is considered to improve students' critical thinking (CT) skills. However, there are several obstacles to implementing this instructional model. PBL is highly time-consuming and creates a high cognitive load, so it is not suitable for all students, especially students with low prior knowledge. To investigate this problem, we conducted a quasi-experiment to study the difference in the improvement of CT skills between students who study using PBL and student who study using PBL with problem posing within-solution (PPWS). The sample of this research is 71 high school students in Mataram City. The result revealed that there was no difference in the enhancement of CT skill between students who learn using PBL and student who learn using PBL with PPWS. This means we can substitute PBL into PBL with PPWS to foster student CT skills.

Learning in higher education is expected to be able to optimize students' critical thinking skills. However, learning mathematics during the pandemic encountered many obstacles affecting students' critical thinking skills. Furthermore, even before the pandemic occurs, mathematics education students still face difficulties optimizing their critical thinking skills. This study aims to analyze the level of critical thinking skills of mathematics education students during the pandemic and the learning models that can be applied to improve these abilities through online learning. The method used is a systematic literature review (SLR) on Google Scholar, ERIC, Science Direct, and DOAJ databases restricted for publish year in 2019-2022. The findings are the level of critical thinking ability of mathematics education students varies depending on the course used in the research. Secondly, several models or learning media can be applied in online classes during the pandemic to improve the critical thinking skills of mathematics education students. Some of them are a combination of Google meet with scaffolding-based online Geogebra, E-Academic based on collaborative learning, PDEODE strategy. The use of Geogebra Javascript, Realistic Mathematics Education approach, Problem Based Learning, using e-books instead conventional books and articles in newspapers as learning media.