Universal key fractions (e.g. an A natural in the scale above becomes ) or, more commonly in written text, by inserting an accidental before the number (e.g. the same note becomes 5 or 4). In music theory aimed towards jazz and popular music, all triads are represented by upper case numerals, followed by a symbol to indicate if it is not a major chord (e.g. "m" for minor or "ø" for half-diminished): When representing the triads rooted in a minor key, accidentals are used to indicate the chromatic alteration from the assumed major key roots indicated by numerals that don't have accidentals:
Key signature signature and no accidentals contains notes of at most seven of the twelve pitch classes, which seven being determined by the particular key signature. Each major and minor key has an associated key signature that sharpens or flattens the notes which are used in its scale. However, it is not uncommon for a piece to be written with a key signature that does not match its key, for example, in some Baroque pieces, or in transcriptions of traditional modal folk tunes. Later on, this use of a key signature that is theoretically incorrect for a piece as a whole or