Musical notation its "natural" form, which means that any sharps or flats applying to that note from the key signature or from accidentals are cancelled. Sometimes a courtesy accidental is used in music where it is not technically required, to remind the musician of what pitch the key signature requires. Following the key signature is the time signature. The time signature typically consists of two numbers, with one of the most common being "4/4". The top "4" indicates that there are four beats per measure (also called bar). The bottom "4" indicates that each of those beats are quarter notes. Measures divide
Key signature or a "sharp" key signature. The key signatures with seven flats () and seven sharps () are rarely used because they have simpler enharmonic equivalents. For example, the key of C major (seven sharps) is more simply represented as D major (five flats). For modern practical purposes these keys are (in twelve tone equal temperament) the same, because C and D are enharmonically the same note. Pieces "are" written in these "extreme" sharp or flat keys, however: for example, Bach's Prelude and Fugue No. 3 from Book 1 of The Well-Tempered Clavier BWV 848 is in C major. The modern