Calculate the natural constant

REM sum = 1/1! + 2/2! + 3/3! + 4/4! + ... + n/n! : n = 10 ' mathemtically we can reduce it to :
REM sum = 1/0! + 1/1! + 1/2! + 1/3! + ... + 1/(n-1)!          [calculate this]
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    let sum = 0
    let factorial = 1
for n = 0 to 100
    if n = 0 then factorial = 1

    if n > 0 then factorial = factorial * (n)

    sum = sum + 1/factorial




next n
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print sum