21 into 10 best min fragment found: 21/5
  Cut up 21 sticks of length 10 like this:
    5 x (5 + 5)
    2 x (24/5 + 26/5)
    2 x (23/5 + 27/5)
    2 x (22/5 + 28/5)
    10 x (21/5 + 29/5)
  Reassemble as 10 sticks of length 21 like this:
    2 x (5 + 5 + 27/5 + 28/5)
    2 x (5 + 5 + 26/5 + 29/5)
    2 x (23/5 + 24/5 + 29/5 + 29/5)
    2 x (22/5 + 5 + 29/5 + 29/5)
    2 x (21/5 + 21/5 + 21/5 + 21/5 + 21/5)