Electronic self-study device

An electronic self-study device comprising:

• input means including a start key for starting a display of a problem;
• ten keys adapted to be depressed by a user to input an answer;
• and a reviewing key adapted to be depressed by a user to again display a problem incorrectly answered by the user;
• problem presenting means coupled to said input means and being responsive to operation of said start key to prepare a problem according to random members;
• display means coupled to said problem presenting means for displaying the problem prepared by said problem presenting means;
• right answer calculating and storing means coupled to said problem presenting means for effecting a calculation with respect to said prepared problem and for storing a right answer corresponding to a result of said calculation;
• answer storing means coupled to said input means for storing an answer to said displayed problem inputted by the user through operation of said ten keys;
• judging means coupled to said right answer calculating and storing means and to said answer storing means for comparing said right answer and said answer inputted by the user, and for producing a wrong signal when said right answer and said inputted answer do not coincide with each other and a right signal when said right answer and said inputted answer do coincide with each other;
• problem storing means coupled to said judging means and to said problem presenting means and being responsive to said wrong signal to store said prepared problem to which said wrong signal corresponds;
• and
• problem readout control means coupled to said input means and to said problem storing means and being responsive to operation of said reviewing key for causing the problem stored in said problem storing means to be read out by the operation of said reviewing key and for delivering said read-out problem to said calculating and storing means and to said display means, whereby when the user inputs an answer to said read-out problem, the correctness thereof is again judged by said judging means.