Riddle: You have 5 cookies to divide equally between 6 children. At the same time, you cannot cut a cookie into 6 equal parts. How would you divide them!
Answer: Divide each cookie into 3 pieces, give 2 pieces each, last 3 pieces divide in half and give 1 to each. Or smash them all into grains, get a weight scale and divide the powder into 6 portions.
You can also wait until the oldest one of them becomes 18 and there you have 5 children and one disqualified adult and 5 rotten cookies, and then it’s your decision if you want to poison them.