Final answer:
A doubly dotted note extends the duration of the note more than a singly dotted note; it adds half of the duration of the first dot to the note's length.
Step-by-step explanation:
A doubly dotted note in music notation signifies that the duration of the note is extended even longer than a singly dotted note. A single dot increases the duration of the note by half of its original value, whereas the addition of a second dot adds half of the value of the first dot. For example, if a quarter note (which typically gets one beat) is doubly dotted, the first dot adds another half beat to it (making it 1.5 beats), and the second dot adds a quarter of the original beat (0.5 * 0.5 = 0.25), so the total duration of the note becomes 1.75 beats.