Unlike chords, scales are played one note at a time. You should be able to see that the C major pentatonic scale uses all the notes from a C chord, plus a couple of extras. Play through the chord ...

Chords are numbered in Roman numerals. For example, in the scale of C major, the chords are numbered like this: An added 6th is a major triad with the addition of a 6th note above the root.

Harmonic minor keys are used when writing chords ... the triads in C major are as follows: Triads can be indicated by Roman numerals of the degrees of the scale. In the jazz styles of Gershwin ...