Primary triad  challenge- to accompany lesson one
The first challenge goes along with Lesson One from Lessons in Harmony.  Prepare to arm yourself !
THE CHALLENGE:  In the Left Hand play the primary triads in the progression I-IV-V-I-V-IV-I in all the major keys going around the Circle of 5ths.  When you feel comfortable with the left hand add both hands.
Here is the challenge in frames in the key of C:  
  • Frame I:  Play an arpeggiated triad in root position (up then down) 2X. This is the I scale degree.
  • Frame 2:  Move down a 5th from the root and play the arpeggiated triad 2X. (Up a 4th is the same thing) This is the IV scale degree.
  • Frame 3: Move up a whole step and play the arpeggiated triad 2X. This is the V scale degree. 
When you have completed these frames come back down playing each triad twice before moving to the next set.
When you finish the first set move down a 5th (or up a 4th) and go through the progressions in the next key (F) and each subsequent key until you have gone through the 12 keys. Set the metronome at 120 bpm and keep your eyes closed. Repeat to yourself the key you are in, the number of flats or sharps, the name of the triad, and the number of the scale degree each time. You should be able to get through all 12 keys under 5 minutes at 120 bpm. Do this until you can get through it without hesitation. Soon you will have not only the Circle of 5ths memorized but also the I-IV-V progressions in all the major keys.  You can practice this away from the piano too.