Ali (R.A.) mathematical brilliance

Mathematics is one of the hardest subjects unless you are one of the few people like Ali (RA), the fourth Khalif. Ali (R.A) was endowed with a sharp mind. He solved in a matter of seconds mathematical problem that had defeated the people of his time. I am not sure if we can answer it before reading how he solved it. Try it and lets see if you managed in the comments section.

A person was about to die, and before dying he wrote his Will which went as follows:

"I have 17 Camels, and I have three sons. Divide my Camels in such a way that my eldest son gets half of them, the second one gets 1/3rd of the total and my youngest son gets 1/9th of the total number of Camels." (Try solving it before reading further)

After his death when the relatives read his will they got extremely perplexed and said to each other that how can we divide 17 camels like this.
So after a long hard thought they decided that there was only one man in Arabia who could help them: "Hazrat Ali (RA)."
So they all came to the door of Ali (RA) and put forward their problem.
Ali (RA) said, "Ok, I will divide the camels as per the man's will."
Ali (RA) said, "I will lend one of my camels to the total which makes it 18 (17+1=18), now lets divide as per his will."

The eldest son gets 1/2 of 18 = 9
The second one gets 1/3 of 18 = 6
The youngest gets 1/9 of 18 = 2
Now the total number of camels = 17 (9+6+2=17)

Then Ali (RA) said, "Now I will take my Camel back.