5afdo (arithmetic frequency division of the octave), or 5odo (otonal division of the octave), divides the octave into five parts of 1/5 each. As a scale it may be known as mode 5 of the harmonic series or the Over-5 scale. As 5 is a small odd number, this AFDO does not contain a perfect fifth or any reasonable approximation to it, an it is relatively poor for its size at creating traditional tonal music compared to 4afdo and 6afdo.