Its a simple calculator application.

To use a calculator application, you can follow these steps:

Open the calculator application on your device.
Enter the numbers you want to perform operations on.
Choose the operation you want to perform (e.g. addition, subtraction, multiplication, division).
Press the "=" button to get the result of the calculation.
Repeat the steps as needed for more calculations.
Note: The exact steps may vary depending on the specific calculator application you are using.