Pentatonic guitar scales [5 tone scales] are possibly the most popular & most used melodic tone groups on our planet. It is often the first complete scale system a student learns. One way we learn them is using frames (grids, maps, charts).
The pentatonic scale is any scale with 5 tones, yet in Western music, it specifically refers to the Major & minor types. Each of these have a specific formula, or set of tonal relationships that create the sound of Major & minor pentatonic. It can be viewed to be a ‘hollowed out’ Major/minor scale system [it is ‘missing’ the 4 & 7 to the Major, & those same tones are the 2 & 6 to the minor].
The Major pentatonic scale formula is R 2 3 5 6. This scale is the main riff in ‘My Girl’.
The minor pentatonic scale formula is R b3 4 5 b7. The same 5 tones, just calling a different tone, the root.
I typically use the term ‘frame’ to refer to this particular set of patterns/positions/fingerings. You may want to take a look at the big maps available at the Nucleus [on the path, we will be building these maps up frame by frame].
For our purposes, we use 2 names [starting points] for this scale. G and Em are relatives in the key signature system [they share the ‘same’ key signature].
We first train the scale [both fingerings/positions]. Once we have it in our hands, we use the tone set to melodically improvise. We also build chords. This is our process for working with scales.
We will begin our pentatonic studies with frame 1 of Em/G in Multiply. This shape is a simple 2 tone per string scale made up of 5 tones [the penta- part]. Within this position, tones are repeated. There are two octaves of E [64 & 41] and two octaves of G [63 & 31].