At the beginning of each piece of music, after the treble clef, you will see two numbers. These numbers are called the time signature.
This indicates 4 beats per bar.
This indicates that each beat is worth a quarter note.
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 in example 1.