title: Rounding up c# giving wrong answer
body: <p>I am programming a stocks/production program for a school project (bike factory) and I have to round some numbers up such as the bikes that have to be produced (due to fallout it are doubles).</p>
  
  <p>If I use the following code:</p>
  
  <pre><code>double test = Math.Ceiling(100 * 1.09);
  
  label75.Text = Convert.ToString(test);
  </code></pre>
  
  <p>I get as an answer 110, but that's not right, it should be 109 (9% of 100). Although it seems to work with values below 9%.</p>
  
  <p>What am I doing wrong?</p>