title: How do I truncate milliseconds off "Ticks" without converting to datetime?
body: <p>I have two times in <code>Ticks</code> like so:</p>
  
  <pre><code>//2016-01-22​T17:34:52.648Z
  var tick1 = 635890808926480754;
  
  //2016-01-22​T17:34:52.000Z
  var tick2 = 635890808920000000;
  </code></pre>
  
  <p>Now as you can see comparing these two numbers <code>tick1 == tick2 returns false</code></p>
  
  <p>although the dates are the same (apart from milliseconds).</p>
  
  <p>I would like to truncate the milliseconds off these numbers without converting it to a datetime (because this would reduce efficiency)</p>
  
  <p>I have looked at <a href="https://msdn.microsoft.com/en-us/library/system.math.round(v=vs.110).aspx" rel="noreferrer">Math.Round</a> which says:</p>
  
  <blockquote>
    <p>Rounds a value to the nearest integer or to the specified number of fractional digits.</p>
  </blockquote>
  
  <p>and also <a href="https://msdn.microsoft.com/en-us/library/c2eabd70(v=vs.110).aspx" rel="noreferrer">Math.Truncate</a> neither of which I think do what I need.</p>
  
  <p>Looking at <a href="https://msdn.microsoft.com/en-us/library/system.datetime.ticks(v=vs.110).aspx" rel="noreferrer">Datetime.Ticks</a> it says:</p>
  
  <blockquote>
    <p>A single tick represents one hundred nanoseconds or one ten-millionth of a second. There are 10,000 ticks in a millisecond, or 10 million ticks in a second.</p>
  </blockquote>
  
  <p>Therefore I need to round the number down to the nearest ten million.</p>
  
  <p>Is this possible?</p>