Apart from No.30, the Hanon exercises mostly cover no greater a span than a sixth - hardly much of a challenge or representative of the demands placed on the modern keyboard player. This series of variations expands the span of the exercises first to a seventh (Nos.1 to 10), and then to the whole octave (Nos.11 to 16).

Care should be taken in developing the hand's ability to maintain this span and at the same time exercise the finger movements asked for. Pupils must 'listen' to their hands and err on the side of caution when judging how much can be achieved without strain in any one practice session.