I would take the 17 cookies (now taking one for the original owner) leaving 16 (ignoring the half for now), divide that by 4 which gives you 4 itself and 4 divided in half is 2, that gives every child 2 cookies except for the original owner ( still one cookie even). Now takethe 1/2 and dived that with 4 and that leaves .6, that means that each kid gets 2.6 cookies while leaving the original owner with one cookie.