title: How to multiply each number by minus the number by 1 in C#?
body: <p>I have a number 10, I want to multiply each number by minus the number by 1 it something like:</p>
  
  <blockquote>
    <p>10! = 10*9*8*7*6*5*4*3*2*1</p>
  </blockquote>
  
  <p>Then the result.
  How to handle this in C#?</p>