The question is wrong, it should be that the second child gets one third and the third child gets one ninth. . . (Because1/2+1/4+1/6 = 1 1 2 doesn't meet the design, or you should be11. The title design of 17 sheep should be1/2+1/3+1/9 =17/18).

(1) 17 sheep, 1/2, 1/3, 1/9.

Borrow one from a neighbor and return it to the neighbor after sharing.

Borrow *** 18 sheep

Nine eldest sons, six second sons and two third sons,

Return the rest.

(1) 1 1 sheep, 1/2, 1/4, 1/6.

Borrow one from a neighbor and return it to the neighbor after sharing.

Borrow *** 12 sheep

Six eldest sons, three second sons and two third sons,

Return the rest.