Students' critical thinking skills in solving on the topic of sequences and series

One of the most important mathematical skills of the 21st century is critical thinking skills. In early 2020 the Indonesian education system implemented online learning due to Covid-19. This study aims to analyze the ability of mathematical critical thinking in solving sequence and series at the time of online learning application. This study uses a qualitative descriptive method with a population of all students in 12th grade on SMA Negeri 25 Garut. The sample was chosen based on purposive sampling, with the subject having studied the sequence and series materials and selected a class of 32 students as a research sample. The instrument used is a test with a description type. The data collection technique is done by providing questions online through a google form. The results showed the mathematical critical thinking skills of 12th-grade students on SMA Negeri 25 Garut in solving sequence and series materials were in the medium category with an average percentage of 56.92%.