arithmetical restorations

It is application to complete an expression using the number that 'arithmetical restorations', a given answer were appointed. During commuting, let's strengthen brain using the time that we had free including the wait! I do not put the unnecessary functions such as thyme limits at all to concentrate on it slowly and carefully, and to be able to think. [How to play] At first I choose the level with a title. Was displayed by a screen; accept a number and a ceremony to answer. The number can choose only a light blue button. If a calculation formula is completed, then press the OK button. If an expression is right, the next question is displayed. When I want to delete an expression, then press CL button. When you want to know the answer, please push the give up button. When I want to try a different level, I push the button of ,up arrow button and return to a title. When you push the operation button more than one second, a problem not to use the operation is displayed.