The story of the 18th camel

There was once an old Arab who died and left 17 camels to his three sons. His will was very explicit about their inheritance. One-half of the camels were to be given to the eldest son, one-third to the middle son, and one-ninth to the youngest son. The sons were extremely perplexed, since seventeen cannot be divided by two, three, and nine. As they were pondering how, in Allah’s name, they might divide up their inheritance without spilling either their own blood or that of the camels, a mullah riding a camel came to their aid. “I will lend you my camel,” he said. With the mullah’s camel there were now eighteen camels. The oldest son took one-half or nine camels; the middle son took one-third or six camels; and the youngest son took one-ninth or two camels. Nine plus six plus two camels totaled 17. The mullah took back his 18th camel and all the sons were happy.”

(retold on the basis of Lynn Segal, The Dream of Reality: Heinz von Foerster’s Constructivism).