Key Signatures

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In regards to knowing sharps and flats, here's a trick: For key signatures that have sharps, always go to the next staff to the last sharp; for key signatures that have flats, always go to the previous staff next to the last flat.

Sharps
C/Am - no sharps (C, D, E, F, G, A, B)

G/Em - 1 sharp (C, D, E, F#, G, A, B)

D/Bm - 2 sharps (C#, D, E, F#, G, A, B)

A/F#m - 3 sharps (C#, D, E, F#, G#, A, B)

E/C#m - 4 sharps (C#, D#, E, F#, G#, A, B)

B/G#m - 5 sharps (C#, D#, E, F$, G#, A#, B)

F#/G#m - 6 sharps (C#, D#, E#, F#, G#, A#, B)

C#/A#m - 7 sharps (C#, D#, E#, G#, A#, B#)

Flats
F/Dm - 1 flat

Bb/Gm - 2 flat

Eb/Cm - 3 flats

Ab/Fm - 4 flats

Db/Bbm - 5 flats

Gb/Dbm - 6 flats (Cb, Db, Ab, Gb,

Cb/Abm - 7 flats (Cb, Db, Eb, Fb Gb, Ab, Bb)

How to find the key of a song
Play, listen to the bass note, determine.