There is a simple system for identifying any note’s position in a bar by naming notes off the beat according to which beat they come directly after. The system works as follows. Within a bar of continuous eighth notes in * time, there are eight possible places where notes could occur.
The first beat is called one (1), the next eighth note is called the "and of one", then comes beat two, the next eighth note is called the "and of two", then beat three, followed by the "and of three", then beat four, followed by the "and of four" which is the final eighth note in the bar. These positions are shown in the following notation.
This symbol is an eighth rest. It indicates half a beat of silence.
When improvising melodies, where you choose not to play notes is as important as where you do play notes. The following example contains an eighth rest on the first two beats of each bar.