As an example, we show below the G Major and Minor Pentatonic scales as well as the G Major and Minor Blues scales. The Pentatonic Major scale consists of the root, second, third, fifth and sixth notes from the Major scale and for the Major Blues scale add the flatted third. The Pentatonic Minor scale consists of the root, flatted third, fourth, fifth and flatted seventh of the Major scale and for the Minor Blues scale add the flatted fifth. Hence, if you remove the "blue notes" from the Blues scales you would then have the Pentatonic scales. The "Root notes" are shown in red. The melody usually begins and/or finishes on the root note and this defines the key. Notice how a box that has the notes beginning on the 12th fret could be transposed to the top of the fretboard with those notes being the open notes in their place.

By utilising the scale/chord tool above, you can determine how to alternate the 5 boxes of these scales with other keys. Alternatively, and this would be a preferable way to learn and remember, determine the key by where the first 'root note' lies on either the the sixth (thickest), fifth or fourth strings. The notes on these strings should be memorized. Of course these scales, the Major scales and others (including the modes) can be shown with the above Java tool. Keep practising and have fun!