Halloween is Sunday and mobs of little sugar-crazed zombies, princesses and superheroes are going to be at your door looking for candy, so you better be prepared. If only there was some sort of mathematical formula to figure out how much candy you should buy. Oh wait, there is.
Delivery company Shipt and Mars Wrigley have figured out a mathematical equation to help you estimate how much candy you'll need. Just multiply Time-by-Kids-by-Generosity. In other words, how many hours do you think you'll be getting trick-or-treaters? Multiple that by the number of neighborhood kids you expect to get at your door each hour. And then multiple that by the number of pieces of candy you expect to give each kid. The sum should tell you exactly how much candy you should have on-hand.
So, if you hand out two fun-sized candies to each of the 40 kids that come by each hour for five hours, then you need to have 400 pieces of candy. And if it's going to rain, divide your total number by 1.5. (Popular Mechanics)