The sign 8—– is usually written above the pentagram and the notes above which it is positioned must be played an octave more . At the end of —— the notes follow their natural position.
The eights instead last an octave, half of a crotchet ( semiminima). They will be doubly faster than those of previous exercises (41-42-43).
In this exercise all the values we have studied are proposed again. From whole note to quaver, gradually growing on speed. It’s crucial to keep time, count the lenght of values, in order to play synchronously 4 handss.
Left and right hand play the same note, so you don’t have problems. I recommend to pay attention to the length of values. If you don’t have a metronome, buy one.