You can choose one of three levels of difficulty Easy, Normal and Hard. As these pictures below, the answer will be somewhere between left and right notes shown respectively, on the musical scale. Easy and Normal levels do not contain "sharp notes". Select a reference tone of either 440Hz, 441Hz or 442Hz. Press the "play" button, and carefully listen to each set of tones. Each question contains five individual notes tuned to equal temperament. These notes are randomly selected and played for each question. Answer the question. Input your answers on each of the interactive music sheets. As you tap your finger on the display, a note will appear. All questions can be played as many times as you wish. You can also modify your answer until you press the "answer" button. Press the "answer" button, which will show your score. Press the "next" button to try for the next challenge.