One rev of motor does 5 revs of chuck as you have said
one rev of motor is 200 steps x 10 microsteps of drive = 2000 steps per rev
steps per rev of chuck is 2000 x 5 = 10,000
10,000 steps per 360 degrees so 1 degree is 10,000/360 = 27.777777777777777777777777777777 steps
Hood