Dotted notes
When a dot is placed after a note, it increases the length of the note by 1/2 of it's original value.
Thus a note worth 1 beat will increase to 1 1/2 beats and a note worth 2 beats will increase to 3 and so on.
Simple and Compound Time
The time signatures you saw on the previous page, e.g. 4/4 are known as simple time
signatures. They are called "simple" because the beat is worth an ordinary note like a
crotchet or quaver.
In Compound Time, the time signatures at first seem more complicated. This is
because the beat is worth a dotted note. We have no way of writing, say, two
dotted crotchet beats per bar, so we split the dotted crotchet into three quavers
which gives us a total of six quavers in the bar. Hence we write 6/8, i.e. six
quavers (eighth notes), but we MEAN two dotted crotchet beats per bar.
Here are some examples:
