An old man died and left seventeen horses to his three sons. His will said: "As the eldest had already been financially independent, he would get one ninth of the horses; the second son had just graduated and was going to work, so he would get one third; the youngest would get half because he was still little."
Obviously, unless a horse was killed, it is a difficult to allot the horses fairly. The three brothers started to quarrel.
Afterwards, a wise man came to mediate the dispute. He offered a horse to take part in the allotment. He promised he would only take back the horse after a fair allotment.
As a result, a miracle appeared. Since there were 18 horses now, the eldest should get two horses for his one-ninth share; the second brother six for his one-third share; the youngest nine for his half share. Two plus six plus nine ... there was still a horse left and it so was returned to the wise man. Everyone was happy about the allotment.