An old Arabian is about to die. He tells his three sons he will leave them his camels.
To the eldest son, he leaves 1/2 of them.
To his second, he leaves 1/3 of them.
To his youngest, he leaves 1/9.
When he died, they discovered that he had 17 camels, and they couldn't think of an even way to divide them without killing any of them.
Just then, an old friend of their fathers came riding along on his camel. They explained the problem to him, and he thought of a way to divide the camels just as the father wished.
How?