n! means n 
(n 
1) ... 3 2 1
(n 1) ... 3 2 1
For example, 10! = 10 9 ... 3 2 1 = 3628800,
and the sum of the digits in the number 10! is 3 + 6 + 2 + 8 + 8 + 0 + 0 = 27.
9 ... 3 2 1 = 3628800,and the sum of the digits in the number 10! is 3 + 6 + 2 + 8 + 8 + 0 + 0 = 27.
Find the sum of the digits in the number 100!
Prelude Data.List.Split> let factorial = product $ enumFromTo 1
Prelude Data.List.Split> sum $ map (\x -> read x :: Int) $ chunksOf 1 $ show $ factorial 100
Loading package split-0.2.2 ... linking ... done.
648
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