The child should be taught to recognize tones, and the spaces between
tones of the scale. Have him stand with his back to the piano and learn
to tell the difference in the tones that are played. First, use the
octave, then the one-five-eight. Next the one-three-five eight; then
the one-two three, etc. Then introduce the half-tones. This exercise
can be made more difficult according to age and musical ability.