Because you have to have the sempre staccato note for your left hand, you do not need to be concerned about achieving a smooth flowing movement like say in a Rondo for example. For the left hand in bar 3, you will have to use finger 5 for the A and then 3 or 4 on E and use the thumb for G and A. The other way would be to use fingers 1 and 2 for the G and A which means more of a stretch as finger 3 has no other choice but to go onto the E. I can make that stretch but it is not comfortable and feels unusual.
Because of the location of the dynamic marking just below the bass clef, the instruction only applies to the bass clef - now there's a piece of theory that will get you extra points on your homework!
Just happened upon this forum and thought I'd throw in an idea.
As markymark correctly pointed out, the whole bass line is 'sempre staccato' (where 'sempre' is literally Italian for 'always' I think).
This gives you a bit of flexibility as you don't need to play 'legato' (where transition from note to note appears seamless).
With this in mind, in bar 3 I would personally use finger 5 for the bottom note, and then fingers 1, 2 and 4 for the chord. The reason for using 4 instead of 3 is because it feels more comfortable for me as my fingers are in their natural position. If I used finger 3, I would be forcing it apart from finger 2.
I hope that made sense!
The fact the bass line is 'sempre staccato' means you don't have to stretch from the bass note to the chord since you will be lifting your hand clear of the piano each time you strike it.
Similarly, in bar 12, I would use 5 for the bass note, then 1, 3 and 5 for the chord.
In summary, the fingers of your hand should be quite compact for the whole piece. The only thing you really need to move is the hand/wrist itself as you lift it up in between striking the notes.
I think one of my old piano teachers likened the movement of the hand to an arch as you moved from one area of the piano to the other.
So yes, hope that helps in some way...
(can't believe I misspelt my username!)
Although you can play the top 2 notes in bar 3 with the thumb, this will onl be necessary if you have a comparatively small hand, narrow spread.
These chords are almost like a stride piano style- aka pete johnson.
Use exercises like these to strengthen your little finger in your left hand, Played fast, all quavers.
C,Top c, E,F,Fsharp, G,Bottom G, Top G
Hope this helps