If you are conducting a choir, you have to sing the starting tones for the different voices, and if you don't have a piano near by, you have to use a tuning fork. If you are a male, you will sing the tones for the women, one octave deeper, and visa versa.

The program will play the tone A (440 hz) for you, and display a chord that you must sing. Solfege does not yet have support for microphone, so you will have to decide yourself if your answer is correct or not.