title: Converting float to NSNumber
body: <p>I am missing something basic, here.  Must have forgotten it.  But basically, I have the following code the purpose  take an NSNumber, convert it to float, multiply it by 2 and return the result to an NSNumber.   I get an error on the last step, and am stumped.  What should I do there.</p>
  
  <pre><code>NSNumber *testNSNumber = [[[NSNumber alloc] initWithFloat:200.0f] autorelease];
  float myfloatvalue = [testNSNumber  floatValue] * -2;
  NSLog(@" Test float value %1.2f \n\n",myfloatvalue);
  [testNSNumber floatValue:myfloatvalue];  // error here is floatValue is not found
  </code></pre>