Click "see inside" to use the custom block! Basically, this is how it works: If I were to do 10! with 5 buckets, a list with 5 items would be created. The following shows what would happen in each list item. Item1: 10*9 Item2: 8*7 Item3: 6*5 Item4: 4*3 Item5: 2*1 In the end, I'd multiply each list item together. (Item1*Item2*Item3*Item4*Item5) The result is the factorial of 10 :D To make "buckets" work, you need to have x be divisible the number of buckets evenly. For example, you can't split 10 into 4 buckets and have the same number of things in each bucket, because 10/4 isn't an even number.