title: Objective-C invalid operands to binary expression
body: <p>I am getting the error:</p>
  
  <blockquote>
    <p>invalid operands to binary expression ('UITextField')</p>
  </blockquote>
  
  <p>my .h looks like this:</p>
  
  <pre><code>@interface ViewController : UIViewController{
  
      IBOutlet UILabel *resultLabel;
      float result;
      IBOutlet UITextField *miles;
      IBOutlet UITextField *mpgLoaded;
      IBOutlet UITextField *mpgEmpty;
      IBOutlet UITextField *fuelCost;
      IBOutlet UITextField *payment;
  }
  
  -(IBAction)result:(id)sender;
  
  -(IBAction)reset:(id)sender;
  
  
  @end
  </code></pre>
  
  <p>And the error is coming from the calculation I am trying to do in .m:</p>
  
  <pre><code>-(IBAction)result:(id)sender{
      result = payment - ((miles/mpgLoaded)*fuelCost)-((miles/mpgEmpty)*fuelCost);
      resultLabel.text = [NSString stringWithFormat:@"%.2f",result];
  }
  </code></pre>