For those who are like me and don’t read directions, you probably won’t read this either, but there is a way to turn off the sound.  On the startup view (the one where you choose the level), in the lower right corner, there is an info button (a round dot with an “i” in the middle).  If you press that button, it will take you to a view where you can turn the sound off.  There are two buttons.  One turns off the background music that plays continuously, and the other one turns off the sounds like the “click” and the happy dance.