We are developing the training system for numerical calculation aiming at improving calculation ability. There are two main purposes of realizing this system. One is to increase students' motivation to study mathematics by using the questions in SPI2 adopted by many companies as employment examinations. The other is to support a student's learning efficiently by giving the questions according to the student's ability. In order to give an adaptive question, our system has functions to estimate each student's ability and item difficulty in the test item database. This paper reports the basic concept, the features and the experiment conducted to verify the usefulness of the system and its result. © 2013 Springer-Verlag.