There is a history function. The input value plus tax, you can switch in the tax. *Function -arithmetic -character Back button -input clear button -± swap reversal button -history display -setting of rounding (truncated, rounded, rounded up) -the character size change -change of tap sound -change of vibration at the time of tap *How to use 1. Enter like a normal calculator. 2. If you press the [=] button it will be recorded in the history. 3. You can change various settings in the [MENU] button. *Note For any damage caused on the use, even if it does not take the author any responsibility, even if it is clear that due to this app. Please use in a range of its own responsibility. *Request Please contact me at the reviews or e-mail if you have any requests or bug. It helps you as much as possible in correspondence.