Answers for all treble and bass flashcards:
Just write the answer on back of each card.  The numbers tell which C or D, for
example, from the low end of the keyboard moving up, a letter is.
From left to right across each page:
C4  D4  C4  D2
E4   F4  A6   B6
D5 E5   G4  A5
F5  G5  B5  C5
F3  G3  B3  C3
A4  B4  D3  E3
E2   F2
G2  A3