20 into 7 best min fragment found: 3
  Cut up 20 sticks of length 7 like this:
    10 x (7)
    10 x (3 + 4)
  Reassemble as 7 sticks of length 20 like this:
    2 x (4 + 4 + 4 + 4 + 4)
    5 x (3 + 3 + 7 + 7)