The objective of this study is to describe the influence of principals' leadership, work environment, and affiliation motivation on improving the performance of certified teachers at Private Vocational Schools in Tegal City, Indonesia. To achieve this objective, the current study carried out a research survey in Private Vocational Schools of Tegal City. Therefore, data collection was achieved by using survey questionnaire and respondents of the study was school teachers. Thus, this study used quantitative research approach with cross-sectional research design. Data were analyzed by using latest technique, namely; Structural Equation Modeling (SEM) based on Partial Least Square (PLS). The results of the study showed that the leadership of the principal, the work environment, and the motivation to affiliate were well perceived by the teachers. Both principal leadership and work environment had direct effects on improving the certified teacher's performance. The teacher's performance can be explained by independent head leadership and work environment variables, however, for independent variables namely; motivation to affiliate did not have enough significant influence. Hence, teacher's performance can be improved through the leadership of principals and a conducive work environment.

The purpose of this study was to determine whether there is any difference between students’ mathematical representation ability who were taught by using the learning model of Project Based Learning with students who were taught by Guided Discovery Learning; there is any difference in the students' mathematical representation ability based on high, medium, or low learning motivation categories, and there is an interaction between the learning model and the learning motivation toward mathematical representation ability. A quasi experiment was used with 2x3 factorial designs. Instrument used to collect data was mathematics test and learning motivation questionnaire. The hypothesis testing used two way analysis of variance with unequal cell. Based on the results of hypothesis testing, it can be concluded that there is a difference in the students' mathematics ability that was taught by using Project Based Learning model with students who were taught by sing Guided Discovery Learning model; there is a difference in the students’mathematical representation ability based on high, medium, or low learning motivation; and there is an interaction between the learning model and the learning motivation on the mathematics ability.

The purpose of this research is to analyze the Flipped classroom learning strategy when combined with gamification as a learning solution during the COVID-19 pandemic and to provide recommendations for teachers, learning designers, and practitioners regarding the implementation of the two learning strategies. This study uses a qualitative content analysis method. Based on the results of the analysis, giving gamification elements into learning has the potential to increase the quality of mathematics learning. Several research results state that the use of the Flipped classroom strategy and the use of gamification have a positive impact on learning so that it can be a suggestion for learning during the COVID 19 pandemic, especially in mathematics learning.