A method for online music learning of playing a musical instrument, that may be a string instrument, a woodwind instrument, a brass instrument, a percussion instrument, or vocal (singing) is described. A client device, such as a smartphone or a tablet notifies a person, such as visually by a display or audibly by a sounder, of a sequence of musical symbols that may be part of a musical piece to be played on the musical instrument. The pace or tempo of the notified sequence is adapted according to a stored skill level value of the person and the pace or tempo associated with the musical piece. The client device, monitors, using a microphone(s) in the client device, the errors in the playing of the sequence, and using a predefined accordingly updates the stored skill level value, and accordingly changes the arrangement, pace and/or tempo of the next sequence of musical symbols.