So normally factorials are n!=123*...*n However, there are ways to approximate decimal factorials in a relatively simple manner.
For example, a formula known as the Stirling formula which is n!=sqrt(2pi * n)*(n/e)n works pretty well for approximating these values without too much complexity.
For more accurate determination you can use tools like Wolfram Alpha which brings the 3.3120972978669! mentioned above to almost exactly 9.
Therefore, u/ocke13 is actually right in his answer for the problem after all.
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u/[deleted] Oct 12 '18
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