title: Incorrect rounding of float when using ToString("F1")
body: <p>I have a float value: 12345.6489</p>
  
  <p>When I format this using:</p>
  
  <p>(12345.6489f).ToString("F1")</p>
  
  <p>Then I get a result of</p>
  
  <p>12345.7</p>
  
  <p>But this is incorrect, since it should be 12345.6.</p>
  
  <p>Does anyone understand why this might occur? Another hint is that casting to double before I format returns the correct result, and if my float value is a little smaller, for example 1234.6489, then too I get the correct result.</p>