The digitalization of education has increased the opportunities for students to write by hand using tablets and other devices. It is not yet clear how the digitalization of handwriting affects handwriting and what points are important to take into consideration. In this study, we focus on writing pressure, which is one of the factors that form handwriting, and clarify how the expression of handwriting with and without pressure affects while solving problems. Specifically, we conducted experiments to clarify the effects of adjustable and non-adjustable pressure on the percentage of correct answers to calculation by writing of the four arithmetic rules and found that the percentage of correct answers in division with presence of grayscale expression was higher.