This paper explores misconceptions and errors (M/Es) of eighth-grade students in Nepal with a quasi-experimental design with nonequivalent control and experimental groups. The treatment was implemented with teaching episodes based on different remedial strategies of addressing students' M/Es. Students of control groups were taught under conventional teaching-learning method, whereas experimental groups were treated with a guided method to treat with misconceptions and errors. The effectiveness of treatment was tested at the end of the intervention. The results showed that the new guided treatment approach was found to be significant to address students' M/Es. Consequently, the students of experimental groups made significant progress in dealing with M/Es in mathematical problem-solving at conceptual, procedural, and application levels.

Momentum-impulse requires critical thinking skills, and teaching should be encouraging for students. Critical thinking skills can be fostered through inquiry-based learning. During the COVID-19 pandemic, familiar learning media were used for students. Therefore, it is necessary to develop creative learning media. This developmental research aimed to create a momentum-impulse e-book based on inquiry supported by infographics (MIB -In-graph) to enhance students' critical thinking skills. The developmental model was a 4D model with field testing, i.e., a pretest-posttest control group design with three classes. Descriptive analysis showed that MIB-In-graph, an Android application, received a good average rating in content, worksheets, and forms. Students’ responses were very positive. Mixed design ANOVA showed that the mean score of students’ critical thinking skills increased significantly from the pretest to the posttest in each class and students’ critical thinking skills in the experimental class was more salient than control class 1 and control class 2. The highest difference in mean scores was in the experimental class. The differences were influenced by various factors such as learning approaches, media use, pictures, and collaboration.