The F major scale starts and ends on the note F, and it contains a Bb note instead of a B note. Exercise 16 shows the note Bb in the key signature, which indicates that it's in the key of F major. If you know which key signatures belong to which key, you can determine the key of any piece by using the key signature. Go back through the book and look for other examples of the key of F major. Try the following F major scale and listen for the Do Re Mi Fa So La Ti Do sound.