Counting and rhythm are what sets music apart from noise. It is all based on simple mathematics. In common time ( 4/4 ) there are four beats per bar or measure.

* A whole note takes the whole measure so it gets four beats.

* A half note takes half of the measure so it gets two beats.

* A quarter note takes one quarter of the measure so it gets one beat.

* An eighth note takes one eighth of the measure so it gets a half beat.

Note: A dot placed beside a note increases it's value by 50%. So a half note with a dot would receive three beats rather than two. A quarter note with a dot would receive 1 and a half beats rather than just one.