20 into 12 best min fragment found: 5
  Cut up 20 sticks of length 12 like this:
    4 x (6 + 6)
    16 x (5 + 7)
  Reassemble as 12 sticks of length 20 like this:
    8 x (6 + 7 + 7)
    4 x (5 + 5 + 5 + 5)