Semi-detached
While Joe was in Hong Kong recently he bought a book of stamps with six stamps per page. From each page it was possible to extract a single stamp or block of stamps (each stamp still attached to at least one other) with any value from 1$ up to the total value of the six stamps. Joe noticed that for most values this could only be achieved in just one way, but for each of four of the values it was possible to select a single stamp or a block of stamps in two ways.
What value were the…
