In general, the difficulty of calculation questions seems to depend mainly on the complexity of the calculation formula and its solution. However, written tests have confirmed that presentations of calculation questions can affect the number of correct responses, even when the solutions use the same calculation formula. Against this background, we have developed a question training system that offers calculation questions based on the relationship between the presentations of the questions and their difficulty. In this paper, we discuss the concept of this system, the strategy for offering questions and the system configuration.