How Can Blended Learning and GeoGebra Promote Students’ Achievement in Calculus during the COVID-19 Pandemic?

: Calculus is one of the most important courses to take, especially for those studying science and engineering because it can help them understand concepts and formulas in these fields. The COVID-19 pandemic impacts learning in universities globally. Observations from three colleges in West Sumatera (Padang State University, Andalas University, and Padang State Polytechnic) revealed that during the COVID-19 pandemic, students' achievement was unsatisfactory due to entirely online calculus lectures. The study's main goal was to see how blended learning and GeoGebra-based Calculus courses affected student achievement in online learning. The population of this study consisted of 224 undergraduate students from Andalas University who were enrolled in Calculus courses in the 2021 academic year's odd semesters, divided into four classes: A1, A2, A3, and A4, whereas the research sample consisted of two classes (A1 and A4) with 114 students randomly selected. Lectures were held seven times in the experiment and control classes, using blended learning and GeoGebra aid in the experiment class and fully online learning in the control class. A four-question midterm test was employed in this study as an instrument. The test is based on the learning objectives of the calculus course and has been declared valid by experts in mathematics and mathematics education. The findings show that using blended learning and GeoGebra to teach and learn calculus positively impacts achievement. More student collaboration, more student-centered knowledge growth and engagement, more flexibility in learning and teaching, and a well-balanced array of learning resources and methodologies are all benefits of blended learning and GeoGebra. A significant difference was in calculus achievement between male and female students, and there was no interaction between gender and learning factors toward calculus achievement in online learning.