Shows up to the last calculation step 300. The rechargeable function with sound assist allows you to check the calculation with sound to check errors. Press the wrong key when performing a second calculation to check the calculation result, the buzzer will alert user error. Displays numbers in 3 digit separator formats (standard, European, India) Large display for more readable data Solar powered if the light is not enough. The key operation is stored in the buffer, so there is nothing at all. Loses even with high speed inputs.