An old man was about to die. He had 17 camels. He decided to share them with his 3 sons in proportion as follows, one half to his eldest son, one third to second son, and one ninth to his last son. But the sons were not able to divide it and fought with each other. A wise man came with his camel and gave them his single camel. Now there were 18 camels. First son got one half of 18 camels, which is 9, second son received one third, which is 6 and last son received one ninth which is 2. Now, 9+6+2=17. One camel remained. The wise man went away with his camel. Whats the math behind it?