Japanese children are wise! Because, it is since this method is performed. method of 10-by-10 trains the power of calculation. method of 10-by-10 trains concentration. method of 10-by-10 raises memory. method of 10-by-10 has an effect to a child. method of 10-by-10 has an effect to an adult. method of 10-by-10 has an effect to an old person. Please use. If a problem will be displayed, an answer will be inputted, if usage is easy, a operator is chosen, the minimum and the maximum are inputted and a start is pushed, and an "answer" button is pushed, the number of correct answers and the number of mistakes will be displayed (a mistake is displayed in the red). It is selection about "it continues", the "following problem", and an "end" button after that. Function The minimum of the number to calculate and the maximum can be decided freely. Addition, subtraction without a negative answer, subtraction with a negative answer It divides and can choose a problem from four (with no input of remainder). Measurement of computation time can be performed. The problem which is different at the same minimum and the maximum is created. The number of correct answers and the number of mistakes are displayed.