At the beginning of each piece of music, after the clef, a time signature is written.
The time signature indicates the number of beats per bar (the top number) and the type of note receiving one beat (the bottom number). For example:
Thus in * time there must be the equivalent of 4 quarter note beats per bat, e.g.:
Most Rock/Pop songs are in * time.
Some other common time signatures are: -
^ indicates 3 quarter note beats per bar, e.g.:
% indicates 2 quarter note beats per bar, e.g.:
) time indicates 2 dotted quarter note beats per bar, which can be divided into 2 groups of eighth notes as such: