First select an animal, followed by operator and the second animal, then click on show result button (=). After getting the result, try to guess the numbers by clicking on the exclamation marks and selecting the guessed number and then clicking on show result button (=) again.

Click on the Settings button and then customize the volumes in the way you like it more.

Click on the Settings button and then hit the Timer Enable check box to turn on/off the timer.