With the contributions of computer technology, digital learning has evolved into a stage of mobile learning. However, school classes require teachers to perform face-to-face humanized lectures. Digital learning remains to function as a tool for assisted teaching. Few studies have investigated what proportions digital learning should occupy in teaching activities. In this study, to investigate the optimal proportion of face-to-face instructions and digital learning, we conducted a one-semester teaching experiment on two classes of students in the informatics department in a public vocational high school in Taipei City. In addition, the Kruskal-Wallis one-way analysis of variance was adopted for the statistical analysis to determine the optimal blending proportions. Our results indicate that optimal effects are achieved at a time ratio of 2:1 of traditional face-to-face teaching to digital learning.