Practice music theory and train your sight reading skills.
• key signatures
• intervals including compound intervals (up to double octave)
• chords including 7th, open voicing, inversions...
• scales including all major scale modes, neapolitan scales...
Practice directly on virtual piano or using simple input buttons.
Many different clefs (treble, bass, soprano, baritone, mezzo-soprano...)
Various note naming schemes: English (CDEFGAB), German (CDEFGAH), Latin (DoReMiFa...)