A simple deck for practicing the major keys, their relative minors, and their key signatures. Each key has three cards. 1) Front: No of sharps or flats, Back: Major and relative minor plus the sharps or flats in the key signature, 2) Front: Major key, Back: Relative minor plus the sharps or flats in the key signature, and 3) Front: Minor key, Back: Relative major plus the sharps or flats in the key signature.
NB This is entirely text-based. There are no graphics of clefs or key signatures.