Under COVID-19 pandemic, blended learning was applied to basic mathematics classes, which was utilised Microsoft Teams as an online communication tool, in order to improve learning. Blended learning means a class method combining face-to-face class and distance class in the course. Also, pre-education of use for Teams was carried out by the domain as the department. The pre-education resulted in improvement of attendance equal to face-to-face class. The learning efficiency was enhanced by face-to-face class added into appropriate turning point of teaching content in the course of classes under on-demand type distance learning. The factors are the relationship between learners and teachers which affects comprehension and motivation for keeping learning. The quality of on-demand type distance learning affects the motivation of learners. It is necessary to present the course content and activities in a way that is easy for students to understand. In order to respond to students with diverse abilities, the quality of each of the face-to-face classes and distance classes needs to be improved, and further consideration of organic combination is needed.