At the beginning of each piece of music, after the treble clef, you will see two numbers. These numbers are called the time signature.
The time signature indicates the number of beats per bar (the top number) and the type of note receiving one beat (the bottom number). This means that the * time signature indicates four quarter notes per bar, as shown:
When playing in * time, it is possible to use any combination of note values which add up to the equivalent of four quarter notes, as shown in the following example. Notice the two dots before the double bar at the end of this example. These dots are a repeat sign and indicate that the example is to be played again from the beginning.
* is the most common time signature and is sometimes represented by this symbol called common time.