The A Minor pentatonic groupings of four exercise is a sequence that takes the pentatonic scale in groupings of four notes from every note in the scale. This type of scale sequence is used in thousands of guitar solos and is something that every guitar player would want be comfortable with.
The Idea is that we play four notes from every note in the scale.
A C D E, C D E G, D E G A, E G A C, G A C D.