[Key features] Perform four fundamental operations and engineering calculations. To start the engineering calculator, tap the engineering calculator icon. To check the calculation history, tap the calculation history icon. To close the calculation history panel, tap the keypad icon. You can use the previously inputted formulas. Tap the formula you need from the calculation history. [Additional features] To convert units, tap the unit calculator button. You can easily convert various types of units, such as area, length, and temperature. This software uses the Apache License 2.0. The details can be found at http://www.apache.org/licenses/LICENSE-2.0.