 Another device predating the problem, is to use extra or marked objects, in this case blue coconuts, to clarify the division process.Suppose that the first sailor before the division, adds four blue coconuts to the pile to guarantee division by 5 (since we know even if he doesn't, that there's going to be a remainder of 1, so adding 4 makes the pile divisible by 5).He divides the pile, takes the fifth with an extra (non-blue) coconut which he tosses to the monkey, hides his share, then puts the rest back together, putting the 4 blue coconuts to the side.